Polymerizable liquid crystal material and polymerized liquid crystal film

ABSTRACT

A polymerizable LC material comprising one or more reactive mesogenic compounds, one or more chiral compounds and a block copolymer that comprises at least one polyfluorooxetane block bonded to a polyether block, said polyfluorooxetane block having a repeating unit of the formula 
     
       
         
         
             
             
         
       
     
     Further, a method for its preparation, a polymer film obtainable from a corresponding polymerizable LC material, a method of preparation of such polymer film, and the use of such polymer film and said polymerizable LC material in optical, electro-optical, decorative or security devices.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. non-provisional application filed under 35U.S.C. § 111(a), claiming priority under 35 U.S.C. § 119(a) of EuropeanApplication No. 20212020.0, filed Dec. 4, 2020 in the European PatentOffice, the entire disclosure of which is incorporated herein byreference for all purposes.

FIELD OF INVENTION

The invention relates to a polymerizable LC material comprising one ormore reactive mesogenic compounds, one or more chiral compounds and ablock copolymer, which comprises at least one polyfluorooxetane blockbonded to a polyether block, said polyfluorooxetane block having arepeating unit of the formula

wherein the individual radicals have one of the meaning as given in theclaims. Furthermore, the present invention relates also to a method forits preparation, a polymer film obtainable from a correspondingpolymerizable LC material, to a method of preparation of such polymerfilm, and to the use of such polymer film and said polymerizable LCmaterial in optical, electro-optical, decorative or security devices.

BACKGROUND AND PRIOR ART

Reactive mesogens (RMs), mixtures or formulations comprising them, andpolymers obtained thereof, can be used to make optical components, likecompensation, retardation or polarisation films, or lenses. Theseoptical components can be used in optical or electrooptical devices likeLC displays. Usually the RMs or RM mixtures are polymerised through theprocess of in-situ polymerisation.

The manufacture of RM film products with high birefringence is of highimportance for manufacturing optical components of modern displaydevices like LCDs. For Example, brightness enhancement films such as 3MDBEF™, are often included in displays in order to increase thebrightness or reduce the number of light sources in the backlight unit.Broadband cholesteric films can also be used for this purpose, and theoptical properties are dependent upon the broadening which can beachieved during processing. Films which are better able to broaden canbe processed faster on a production line, and additionally can haveimproved optical properties.

In this regard, it is possible to polymerise cholesteric reactivemesogen films such that a gradient in the helical pitch is obtained,thereby broadening the reflection band of the film. Thin films with goodoptical properties are dependent on the inclusion of at least onesuitable high birefringence RM.

Broadening of cholesteric films is dictated by the structure of the highbirefringence material in the reactive mesogen mixture. Compounds mustbe highly birefringent and allow band broadening to occur whilst alsohaving good solubility and a broad nematic range, preferably withoutmelting points becoming too high. High birefringence reactive mesogensmade to date with these characteristics only allow cholesteric films tobe broadened by a certain amount before films become hazy.

Increasing the birefringence of the RM whilst keeping them polymerizableand with good physical properties is possible, but requires theincorporation of specific chemical groups, like for example tolanegroups, into the compounds.

Mesogenic tolane derivatives are known for example from U.S. Pat. No.6,514,578 B1, GB 2 388 599 B1, U.S. Pat. No. 7,597,942 B1, US2003-072893 A1 and US 2006-0119783 A1.

Generally tolane groups are relatively reactive and are mostly unsuitedto light exposure, making them difficult to utilize in many opticalapplications due to yellowing or other degradation effects. Furthermore,mesogenic tolane derivatives often show a limited solubility in RMmixtures and are therefore limited in their use.

Furthermore, Cholesteric liquid crystal (CLC) materials, when formedinto thin layers with planar alignment, i.e. wherein the cholesterichelix axis is oriented substantially perpendicular to the plane of thelayer, exhibit the well-known effect of selective reflection of light,where the wavelength of the reflected light is dependent on the pitch ofthe cholesteric helix. By using polymerizable CLC materials, the alignedCLC layer can be converted to a coherent polymer film that retains theselective reflection properties of the original material.

CLC polymer films are known in prior art and have been proposed for avariety of uses, for example as broadband or notch polarizers, as colourfilters in displays or projection systems, and for decorative andsecurity purposes, like the preparation of colored image films orcholesteric pigment flakes.

For some applications, it is desirable to form a multilayer cholestericfilm, comprising two or more cholesteric layers e.g. exhibitingdifferent reflection wavelength.

Multilayer cholesteric polymer films have been described in prior art,such as U.S. Pat. No. 6,417,902. Moreover, EP 0 634 674 suggests toprepare a multilayer cholesteric liquid crystal polymer film by bringingtogether a pair of chiral nematic liquid crystal polymer films, applyingpressure and heating the polymers above their glass transitiontemperature to allow the films to adhere.

Maurer et al., SID 90 Digest, Vol. 21, pp. 110 (1990) describes apolarizing colour filter obtained by combining several polarizing filmswith different reflection wavelength. For the preparation of each film,a layer of a CLC side chain polysiloxane comprising chiral and achiralside groups is brought between two glass plates and oriented by shearingat high temperatures.

JP 01-133003-A (Sumitomo Chem. Ind.) and JP 08-271731-A (Nitto Denko)disclose polarizing plates that are obtained by lamination of one ormore CLC polymer layers onto a quarter wave plate.

However, the methods of preparing multilayer cholesteric films asdescribed in the above documents bear several disadvantages. Thus, it isoften very difficult and requires high temperatures to achieve uniformalignment in the CLC polymer layer. For example, Maurer et al. mentionsan aligning temperature of 150° C., whereas JP 01-133003-A and JP08-271731-A mention that temperatures well above the glass temperatureof the CLC polymers are required. This is especially disadvantageouswhen polymers with high glass temperatures, like acrylates, styrenes ormethacrylates are used, and is highly unsuitable in particular for massproduction.

Furthermore, according to the method of multilayer preparation asdescribed e.g. in JP 01-133003-A, the polymers have to be selected suchthat the different polymer layers exhibit different glass temperatures.Thus, when laminating and aligning e.g. a second layer on top of a firstlayer, the aligning temperature (and thus the glass temperature) of thesecond layer has to be lower than the glass temperature of the firstlayer, so as not to affect the uniform orientation of the first layer,etc. This severely limits the choice of suitable materials and makes theproduction process more complicated.

Another aspect is, that polymerizable LC materials comprising a levelingagents such as a surfactant are usually required in order to achievegood alignment of the resulting CLC polymer. Typically, withoututilizing a surfactant in the formulation, increased haze, bad alignmentof the helix in the CLC polymer and inhomogeneous thickness across thefilm can be observed. On the other hand, due to the levelling agentsnormally used in such formulations, it can be difficult to achieve goodalignment and coating qualities with the second coating of CLC materialwhich is required for multilayer applications.

In this regard, dewetting is defined as the rupture of a thin liquidfilm on the substrate and the formation of droplets. In the case of amultilayer application, this can lead to inhomogeneous thickness of thesecond CLC material when drying. In some cases, the film can recede fromthe edges and in the worst case there is extreme beading of the secondcoated layer which leads to zero coverage of the coated area.

SUMMARY OF THE INVENTION

It is therefore an aim of the present invention to provide improvedpolymerizable LC materials or RM mixtures and RM formulations, which donot have the drawbacks of materials known from prior art. In particularit is an aim to provide RM mixtures and RM formulations that aresuitable for preparing polymers by in situ UV photopolymerization, andexhibit at the same time a high birefringence, exhibit a goodsolubility, show an improved broadening potential, have favorabletransition temperatures, and show high resistance against yellowingafter being exposed to UV light. Another aim is to provide improvedmultilayer stack that does not show the drawbacks of materials knownfrom prior art. Other aims of the invention are immediately evident tothe expert from the following description.

Surprisingly, the inventors of the present invention have found thatpolymerizable LC materials in accordance with the invention fulfill oneor more of the above defined requirements and preferably reaches allaims at the same time.

The invention relates to a polymerizable LC material comprising one orreactive mesogenic compounds, one or more chiral compounds and a blockcopolymer, which comprises at least one polyfluorooxetane block bondedto a polyether block, wherein said polyfluorooxetane block having arepeating unit of the formula

wherein each

-   n and m are each and independently an integer from 1 to 6,-   R is hydrogen or an alkyl group having from 1 to 6 carbon atoms,-   R_(f) and R_(f*) are each and independently a linear or branched    alkyl group of from 1 to about 20 carbon atoms with a minimum of 50%    of the hydrogen atoms of said R_(f) or R_(f*) alkyl group being    replaced by F, and optionally up to all of the remaining H atoms    being replaced by I, Cl, or Br,-   DP is from 2 to about 100.

Further, the invention also relates to a corresponding method ofproduction for the polymerizable LC material comprising at least thestep of mixing one or more reactive mesogenic compounds, one or morechiral mesogenic compounds and a block copolymer.

The invention further relates to a polymer network or polymer filmobtainable, preferably obtained, from the polymerizable LC material, asdescribed above and below and to a method of production of a polymerfilm, as described above and below.

The invention further relates to a method of improving the dewettingbehaviour of a polymer film, obtainable, preferably obtained, from apolymerizable LC material as described above and below, by adding ablock copolymer as described above and below to the polymerizable LCmaterial before polymerization.

The invention further relates to an optical component comprising one ormore optical films of which one is selected from the polymer filmsobtainable from polymerizable LC materials as described above and below.

The invention further relates to the use of a optical component or apolymer film or a polymerizable LC material, as described above andbelow, in optical, electrooptical, information storage, decorative andsecurity applications, like liquid crystal displays, projection systems,polarisers, compensators, alignment layers, circular polarisers, colourfilters, decorative images, liquid crystal pigments, reflective filmswith spatially varying reflection colours, multicolour images,non-forgeable documents like identity or credit cards or banknotes.

The invention further relates to an electrooptical device, such as anLCD or an OLED comprising one or more optical components or polymerfilms or polymerizable LC materials, as described above and below.

The invention further relates to electrooptical device in the field ofaugmented or virtual reality such as head mounted devices comprising oneor more optical components, a polymer film of a polymerizable materialas described above and below.

Terms and Definitions

As used herein, the term “polymer” will be understood to mean a moleculethat encompasses a backbone of one or more distinct types of repeatingunits (the smallest constitutional unit of the molecule) and isinclusive of the commonly known terms “oligomer”, “copolymer”,“homopolymer” and the like. Further, it will be understood that the termpolymer is inclusive of, in addition to the polymer itself, residuesfrom initiators, catalysts, and other elements attendant to thesynthesis of such a polymer, where such residues are understood as notbeing covalently incorporated thereto. Further, such residues and otherelements, while normally removed during post polymerization purificationprocesses, are typically mixed or co-mingled with the polymer such thatthey generally remain with the polymer when it is transferred betweenvessels or between solvents or dispersion media.

The term “(meth)acrylic polymer” as used in the present inventionincludes a polymer obtained from acrylic monomers, a polymer obtainablefrom methacrylic monomers, and a corresponding co-polymer obtainablefrom mixtures of such monomers.

The term “polymerization” means the chemical process to form a polymerby bonding together multiple polymerizable groups or polymer precursors(polymerizable compounds) containing such polymerizable groups.

The terms “film” and “layer” include rigid or flexible, self-supportingor freestanding films with mechanical stability, as well as coatings orlayers on a supporting substrate or between two substrates.

The term “liquid crystal” or “LC” relates to materials havingliquid-crystalline mesophases in some temperature ranges (thermotropicLCs) or in some concentration ranges in solutions (lyotropic LCs). Theyobligatorily contain mesogenic compounds.

The terms “mesogenic compound” and “liquid crystal compound” mean acompound comprising one or more calamitic (rod- or board/lath-shaped) ordiscotic (disk-shaped) mesogenic groups. The term “mesogenic group”means a group with the ability to induce liquid-crystalline phase (ormesophase) behaviour. The compounds comprising mesogenic groups do notnecessarily have to exhibit a liquid-crystalline mesophase themselves.It is also possible that they show liquid-crystalline mesophases only inmixtures with other compounds, or when the mesogenic compounds ormaterials, or the mixtures thereof, are polymerized. This includeslow-molecular-weight non-reactive liquid-crystalline compounds, reactiveor polymerizable liquid-crystalline compounds, and liquid-crystallinepolymers.

A calamitic mesogenic group is usually comprising a mesogenic coreconsisting of one or more aromatic or non-aromatic cyclic groupsconnected to each other directly or via linkage groups, optionallycomprising terminal groups attached to the ends of the mesogenic core,and optionally comprising one or more lateral groups attached to thelong side of the mesogenic core, wherein these terminal and lateralgroups are usually selected e.g. from carbyl or hydrocarbyl groups,polar groups like halogen, nitro, hydroxy, etc., or polymerizablegroups.

The term “reactive mesogen” means a polymerizable mesogenic or liquidcrystal compound, preferably a monomeric compound. These compounds canbe used as pure compounds or as mixtures of reactive mesogens with othercompounds functioning as photoinitiators, inhibitors, surfactants,stabilizers, chain transfer agents, non-polymerizable compounds, etc.

Polymerizable compounds with one polymerizable group are also referredto as “monoreactive” compounds, compounds with two polymerizable groupsas “direactive” compounds, and compounds with more than twopolymerizable groups as “multireactive” compounds. Compounds without apolymerizable group are also referred to as “non-reactive ornon-polymerizable” compounds.

The term “non-mesogenic compound or material” means a compound ormaterial that does not contain a mesogenic group as defined above.

Visible light is electromagnetic radiation that has wavelength in arange from about 400 nm to about 740 nm. Ultraviolet (UV) light iselectromagnetic radiation with a wavelength in a range from about 200 nmto about 450 nm.

The Irradiance (E_(e)) or radiation power is defined as the power ofelectromagnetic radiation (dθ) per unit area (dA) incident on a surface:

E _(e) =dθ/dA.

The radiant exposure or radiation dose (H_(e)), is as the irradiance orradiation power (E_(e)) per time (t):

H _(e) =E _(e) ·t.

All temperatures, such as, for example, the melting point T(C,N) orT(C,S), the transition from the smectic (S) to the nematic (N) phaseT(S,N) and the clearing point T(N,I) of the liquid crystals, are quotedin degrees Celsius. All temperature differences are quoted indifferential degrees.

The term “clearing point” means the temperature at which the transitionbetween the mesophase with the highest temperature range and theisotropic phase occurs.

The term “director” is known in prior art and means the preferredorientation direction of the long molecular axes (in case of calamiticcompounds) or short molecular axes (in case of discotic compounds) ofthe liquid-crystalline or RM molecules. In case of uniaxial ordering ofsuch anisotropic molecules, the director is the axis of anisotropy.

The term “alignment” or “orientation” relates to alignment(orientational ordering) of anisotropic units of material such as smallmolecules or fragments of big molecules in a common direction named“alignment direction”. In an aligned layer of liquid-crystalline or RMmaterial the liquid-crystalline director coincides with the alignmentdirection so that the alignment direction corresponds to the directionof the anisotropy axis of the material.

The terms “uniform orientation” or “uniform alignment” of anliquid-crystalline or RM material, for example in a layer of thematerial, mean that the long molecular axes (in case of calamiticcompounds) or the short molecular axes (in case of discotic compounds)of the liquid-crystalline or RM molecules are oriented substantially inthe same direction. In other words, the lines of liquid-crystallinedirector are parallel.

The term “homeotropic structure” or “homeotropic orientation” refers toa film wherein the optical axis is substantially perpendicular to thefilm plane.

The term “planar structure” or “planar orientation” refers to a filmwherein the optical axis is substantially parallel to the film plane.

The term “A plate” refers to an optical retarder utilizing a layer ofuniaxially birefringent material with its extraordinary axis orientedparallel to the plane of the layer.

The term “C plate” refers to an optical retarder utilizing a layer ofuniaxially birefringent material with its extraordinary axis orientedperpendicular to the plane of the layer.

In A/C-plates comprising optically uniaxial birefringent liquid crystalmaterial with uniform orientation, the optical axis of the film is givenby the direction of the extraordinary axis. An A (or C) plate comprisingoptically uniaxial birefringent material with positive birefringence isalso referred to as “positive A (or C) plate” or “+A (or +C) plate”.

An A (or C) plate comprising a film of optically uniaxial birefringentmaterial with negative birefringence, such as discotic anisotropicmaterials is also referred to as “negative A (or C) plate” or “−A (or C)plate” depending on the orientation of the discotic materials. A filmmade from a cholesteric calamitic material with a reflection band in theUV part of the spectrum also has the optics of a negative C plate.

The birefringence Δn is defined as follows

Δn=n _(e) −n _(o)

wherein n_(e) is the extraordinary refractive index and n_(o) is theordinary refractive index, and the average effective refractive indexn_(av.) is given by the following equation:

n _(av.)=((2n _(o) ² +n _(e) ²)/3)^(1/2)

The average effective refractive index n_(av.) and the ordinaryrefractive index n_(o) can be measured using an Abbe refractometer. Δncan then be calculated from the above equations.

Unless the context clearly indicates otherwise, as used herein pluralforms of the terms herein are to be construed as including the singularform and vice versa.

All physical properties have been and are determined according to “MerckLiquid Crystals, Physical Properties of Liquid Crystals”, StatusNovember 1997, Merck KGaA, Germany and are given for a temperature of20° C., unless explicitly stated otherwise. The optical anisotropy (Δn)is determined at a wavelength of 589.3 nm

In case of doubt the definitions as given in C. Tschierske, G. Pelzl andS. Diele, Angew. Chem. 2004, 116, 6340-6368 shall apply.

Unless explicitly stated otherwise in the given generic formulae, thefollowing terms have the following meanings:

“Carbyl group” denotes a mono- or polyvalent organic group containingone or more carbon atom which either contains no further atoms (such as,for example, —C≡C—) or optionally contains one or more further atoms,such as, for example, N, O, S, P, Si, Se, As, Te or Ge (for examplecarbonyl, etc.). “Hydrocarbyl group” denotes a carbyl group, whichadditionally contains one or more H atoms and optionally one or moreheteroatoms, such as, for example, N, O, S, P, Si, Se, As, Te or Ge.

A carbyl or hydrocarbyl group can be a saturated or unsaturated group.Unsaturated groups are, for example, aryl, alkenyl, or alkinyl groups. Acarbyl or hydrocarbyl group having more than 3 C atoms can be straightchain, branched and/or cyclic and may contain spiro links or condensedrings.

Preferred carbyl and hydrocarbyl groups are optionally substitutedalkyl, alkenyl, alkinyl, alkoxy, alkylcarbonyl, alkoxycarbonyl,alkylcarbonyloxy and alkoxycarbonyloxy having 1 to 40, preferably 1 to25, particularly preferably 1 to 18 C atoms, optionally substituted arylor aryloxy having 6 to 40, preferably 6 to 25 C atoms, or optionallysubstituted alkylaryl, arylalkyl, alkylaryloxy, arylalkyloxy,arylcarbonyl, aryloxycarbonyl, arylcarbonyloxy and aryloxycarbonyloxyhaving 6 to 40, preferably 6 to 25 C atoms. Further preferred carbyl andhydrocarbyl groups are C₁-C₄₀ alkyl, C₂-C₄₀ alkenyl, C₂-C₄₀ alkinyl,C₃-C₄₀ allyl, C₄-C₄₀ alkyldienyl, C₄-C₄₀ polyenyl, C₆-C₄₀ aryl, C₆-C₄₀alkylaryl, C₆-C₄₀ arylalkyl, C₆-C₄₀ alkylaryloxy, C₆-C₄₀ arylalkyloxy,C₂-C₄₀ heteroaryl, C₄-C₄₀ cycloalkyl, C₄-C₄₀ cycloalkenyl, etc.Particular preference is given to C₁-C₂₂ alkyl, C₂-C₂₂ alkenyl, C₂-C₂₂alkinyl, C₃-C₂₂ allyl, C₄-C₂₂ alkyldienyl, C₆-C₁₂ aryl, C₆-C₂₀arylalkyl, and C₂-C₂₀ heteroaryl.

Further preferred carbyl and hydrocarbyl groups are straight-chain,branched or cyclic alkyl radicals having 1 to 40, preferably 1 to 25 Catoms, more preferably 1 to 12 C atoms, which are unsubstituted or mono-or polysubstituted by F, Cl, Br, I or CN and in which one or morenon-adjacent CH₂ groups may each be replaced, independently of oneanother, by —C(R^(x))═C(R^(x))—, —C≡C—, —N(R^(x))—, —O—, —S—, —CO—,—CO—O—, —O—CO—, —O—CO—O— in such a way that O and/or S atoms are notlinked directly to one another.

Above, R^(x) preferably denotes H, halogen, a straight-chain, branchedor cyclic alkyl chain having 1 to 25 C atoms, in which, in addition, oneor more non-adjacent C atoms may be replaced by —O—, —S—, —CO—, —CO—O—,—O—CO—, —O—CO—O—, and in which one or more H atoms may be replaced byfluorine, an optionally substituted aryl or aryloxy group having 6 to 40C atoms or an optionally substituted heteroaryl or heteroaryloxy grouphaving 2 to 40 C atoms.

Preferred alkyl groups are, for example, methyl, ethyl, n-propyl,isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, 2-methylbutyl, n-pentyl,s-pentyl, n-hexyl, 2-ethylhexyl, n-heptyl, n-octyl, n-nonyl, n-decyl,n-undecyl, n-dodecyl, dodecanyl, trifluoromethyl, perfluoro-n-butyl,2,2,2-trifluoroethyl, perfluorooctyl, perfluorohexyl, etc, in which, inaddition, one or more non-adjacent CH₂ groups may each be replaced,independently of one another, by

Preferred alkenyl groups are, for example, ethenyl, propenyl, butenyl,pentenyl, cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, cycloheptenyl,octenyl, cyclooctenyl, etc.

Preferred alkinyl groups are, for example, ethynyl, propynyl, butynyl,pentynyl, hexynyl, octynyl, etc.

Preferred alkoxy groups are, for example, methoxy, ethoxy,2-methoxy-ethoxy, n-propoxy, i-propoxy, n-butoxy, i-butoxy, s-butoxy,t-butoxy, 2-methylbutoxy, n-pentoxy, n-hexoxy, n-heptyloxy, n-octyloxy,n-nonyloxy, n-decyloxy, n-undecyloxy, n-dodecyloxy, etc, in which, inaddition, one or more non-adjacent CH₂ groups may each be replaced,independently of one another, by

Preferred amino groups are, for example, dimethylamino, methylamino,methylphenylamino, phenylamino, etc.

Aryl and heteroaryl groups can be monocyclic or polycyclic, i.e. theycan have one ring (such as, for example, phenyl) or two or more rings,which may also be fused (such as, for example, naphthyl) or covalentlylinked (such as, for example, biphenyl), or contain a combination offused and linked rings. Heteroaryl groups contain one or moreheteroatoms, preferably selected from O, N, S, and Se.

Preference is given to mono-, bi-, or tricyclic aryl groups having 6 to25 C atoms and mono-, bi- or tricyclic heteroaryl groups having 2 to 25C atoms, which optionally contain fused rings, and which are optionallysubstituted. Preference is furthermore given to 5-, 6-, or 7-memberedaryl and heteroaryl groups, in which, in addition, one or more CH groupsmay be replaced by N, S, or O in such a way that O atoms and/or S atomsare not linked directly to one another.

Preferred aryl groups are, for example, phenyl, biphenyl, terphenyl,[1,1′:3′,1″]terphenyl-2′-yl, naphthyl, anthracene, binaphthyl,phenanthrene, pyrene, dihydropyrene, chrysene, perylene, tetracene,pentacene, benzo-pyrene, fluorene, indene, indenofluorene,spirobifluorene, etc.

Preferred heteroaryl groups are, for example, 5-membered rings, such aspyrrole, pyrazole, imidazole, 1,2,3-triazole, 1,2,4-triazole, tetrazole,furan, thiophene, selenophene, oxazole, isoxazole, 1,2-thiazole,1,3-thiazole, 1,2,3-oxadiazole, 1,2,4-oxadiazole, 1,2,5-oxadiazole,1,3,4-oxadiazole, 1,2,3-thiadiazole, 1,2,4-thiadiazole,1,2,5-thiadiazole, 1,3,4-thiadiazole, 6-membered rings, such aspyridine, pyridazine, pyrimidine, pyrazine, 1,3,5-triazine,1,2,4-triazine, 1,2,3-triazine, 1,2,4,5-tetrazine, 1,2,3,4-tetrazine,1,2,3,5-tetrazine, or condensed groups, such as indole, iso-indole,indolizine, indazole, benzimidazole, benzotriazole, purine,naphth-imidazole, phenanthrimidazole, pyridimidazole, pyrazinimidazole,quinoxalinimidazole, benzoxazole, naphthoxazole, anthroxazole,phenanthroxazole, isoxazole, benzothiazole, benzofuran, isobenzofuran,dibenzofuran, quinoline, isoquinoline, pteridine, benzo-5,6-quinoline,benzo-6,7-quinoline, benzo-7,8-quinoline, benzoisoquinoline, acridine,phenothiazine, phenoxazine, benzopyridazine, benzopyrimidine,quinoxaline, phenazine, naphthyridine, azacarbazole, benzocarboline,phenanthridine, phenanthroline, thieno[2,3b]thiophene,thieno[3,2b]thiophene, dithienothiophene, isobenzothiophene,dibenzothiophene, benzothiadiazothiophene, or combinations of thesegroups. The heteroaryl groups may also be substituted by alkyl, alkoxy,thioalkyl, fluorine, fluoroalkyl or further aryl or heteroaryl groups.

The (non-aromatic) alicyclic and heterocyclic groups encompass bothsaturated rings, i.e. those that contain exclusively single bonds, andpartially unsaturated rings, i.e. those that may also contain multiplebonds. Heterocyclic rings contain one or more heteroatoms, preferablyselected from Si, O, N, S, and Se.

The (non-aromatic) alicyclic and heterocyclic groups can be monocyclic,i.e. contain only one ring (such as, for example, cyclohexane), orpolycyclic, i.e. contain a plurality of rings (such as, for example,decahydronaphthalene or bicyclooctane). Particular preference is givento saturated groups. Preference is furthermore given to mono-, bi-, ortricyclic groups having 3 to 25 C atoms, which optionally contain fusedrings and which are optionally substituted. Preference is furthermoregiven to 5-, 6-, 7- or 8-membered carbocyclic groups in which, inaddition, one or more C atoms may be replaced by Si and/or one or moreCH groups may be replaced by N and/or one or more non-adjacent CH₂groups may be replaced by —O— and/or —S—.

Preferred alicyclic and heterocyclic groups are, for example, 5-memberedgroups, such as cyclopentane, tetrahydrofuran, tetrahydrothiofuran,pyrrolidine, 6-membered groups, such as cyclohexane, silinane,cyclohexene, tetrahydropyran, tetrahydrothiopyran, 1,3-dioxane,1,3-dithiane, piperidine, 7-membered groups, such as cycloheptane, andfused groups, such as tetrahydronaphthalene, decahydronaphthalene,indane, bicyclo[1.1.1]-pentane-1,3-diyl, bicyclo[2.2.2]octane-1,4-diyl,spiro[3.3]heptane-2,6-diyl, octahydro-4,7-methanoindane-2,5-diyl.

The aryl, heteroaryl, (non-aromatic) alicyclic and heterocyclic groupsoptionally have one or more substituents, which are preferably selectedfrom the group comprising silyl, sulfo, sulfonyl, formyl, amine, imine,nitrile, mercapto, nitro, halogen, C₁₋₁₂ alkyl, C₆₋₁₂ aryl, C₁₋₁₂alkoxy, hydroxyl, or combinations of these groups.

Preferred substituents are, for example, solubility-promoting groups,such as alkyl or alkoxy, electron-withdrawing groups, such as fluorine,nitro or nitrile, or substituents for increasing the glass transitiontemperature (Tg) in the polymer, in particular bulky groups, such as,for example, t-butyl or optionally substituted aryl groups.

Preferred substituents, also referred to as “L” below, are, for example,F, Cl, Br, I, —OH, —CN, —NO₂, —NCO, —NCS, —OCN, —SCN, —C(═O)N(R^(x))₂,—C(═O)Y^(x), —C(═O)R^(x), —C(═O)OR^(x), —N(R^(x))₂, in which R^(x) hasthe above-mentioned meaning, and above Y^(x) denotes halogen, optionallysubstituted silyl, optionally substituted aryl or heteroaryl having 4 to40, preferably 4 to 20 ring atoms, and straight-chain or branched alkyl,alkenyl, alkinyl, alkoxy, alkylcarbonyl, alkoxycarbonyl,alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 25 C atoms, in whichone or more H atoms may optionally be replaced by F or Cl.

“Substituted silyl or aryl” preferably means substituted by halogen,—CN, R^(y), —OR^(y), —CO—R^(y), —CO—O—R^(y), —O—CO—R^(y) or—O—CO—O—R^(y), in which R^(y) denotes H, a straight-chain, branched orcyclic alkyl chain having 1 to 12 C atoms.

In the formula shown above and below, a substituted phenylene ring

is preferably

in which L has, on each occurrence identically or differently, one ofthe meanings given above and below, and is preferably F, Cl, CN, NO₂,CH₃, C₂H₅, C(CH₃)₃, CH(CH₃)₂, CH₂CH(CH₃)C₂H₅, OCH₃, OC₂H₅, COCH₃,COC₂H₅, COOCH₃, COOC₂H₅, CF₃, OCF₃, OCHF₂, OC₂F₅ or P-Sp-, verypreferably F, Cl, CN, CH₃, C₂H₅, OCH₃, COCH₃, OCF₃ or P-Sp-, mostpreferably F, Cl, CH₃, OCH₃, COCH₃ or OCF₃.

“Halogen” denotes F, Cl, Br or I, preferably F or Cl, more preferably F.

“Polymerizable groups” (P) are preferably selected from groupscontaining a C═C double bond or C≡C triple bond, and groups which aresuitable for polymerization with ring opening, such as, for example,oxetane or epoxide groups.

Preferably, polymerizable groups (P) are selected from the groupconsisting of CH₂═CW¹—COO—, CH₂═CW¹—CO—,

CH₂═CW²—(O)_(k3)—, CW¹═CH—CO—(O)_(k3)—, CW¹═CH—CO—NH—, CH₂═CW¹—CO—NH—,CH₃—CH═CH—O—, (CH₂═CH)₂CH—OCO—, (CH₂═CH—CH₂)₂CH—OCO—, (CH₂═CH)₂CH—O—,(CH₂═CH—CH₂)₂N—, (CH₂═CH—CH₂)₂N—CO—, CH₂═CW¹—CO—NH—,CH₂═CH—(COO)_(k1)-Phe-(O)_(k2)—, CH₂═CH—(CO)_(k1)-Phe-(O)_(k2)—,Phe-CH═CH—, in whichW¹ denotes H, F, Cl, CN, CF₃, phenyl or alkyl having 1 to 5 C atoms, inparticular H, F, Cl or CH₃,W² denotes H or alkyl having 1 to 5 C atoms, in particular H, methyl,ethyl or n-propyl,W³ and W⁴ each, independently of one another, denote H, Cl or alkylhaving 1 to 5 C atoms, Phe denotes 1,4-phenylene, which is optionallysubstituted by one or more radicals L as being defined above but beingdifferent from P-Sp, preferably preferred substituents L are F, Cl, CN,NO₂, CH₃, C₂H₅, OCH₃, OC₂H₅, COCH₃, COC₂H₅, COOCH₃, COOC₂H₅, CF₃, OCF₃,OCHF₂, OC₂F₅, furthermore phenyl, andk₁, k₂ and k₃ each, independently of one another, denote 0 or 1, k₃preferably denotes 1, and k₄ is an integer from 1 to 10.

Particularly preferred polymerizable groups P are CH₂═CH—COO—,CH₂═C(CH₃)—COO—, CH₂═CF—COO—, CH₂═CH—, CH₂═CH—O—, (CH₂═CH)₂CH—OCO—,(CH₂═CH)₂CH—O—,

in which W² denotes H or alkyl having 1 to 5 C atoms, in particular H,methyl, ethyl or n-propyl,

Further preferred polymerizable groups (P) are vinyloxy, acrylate,methacrylate, fluoroacrylate, chloroacrylate, oxetane and epoxide, mostpreferably acrylate or methacrylate, in particular acrylate.

Preferably, all multireactive polymerizable compounds and sub-formulaethereof contain instead of one or more radicals P-Sp-, one or morebranched radicals containing two or more polymerizable groups P(multireactive polymerizable radicals).

Suitable radicals of this type, and polymerizable compounds containingthem, are described, for example, in U.S. Pat. No. 7,060,200 B1 or US2006/0172090 A1.

Particular preference is given to multireactive polymerizable radicalsselected from the following formulae:

—X-alkyl-CHP^(x)—CH₂—CH₂P^(y)  I*a

—X-alkyl-C(CH₂P^(x))(CH₂P^(y))—CH₂P^(z)  I*b

—X-alkyl-CHP^(x)CHP^(y)—CH₂P^(z)  I*c

—X-alkyl-C(CH₂P^(x))(CH₂P^(y))—C_(aa)H_(2aa+1)  I*d

—X-alkyl-CHP^(x)—CH₂P^(y)  I*e

—X-alkyl-CHP^(x)P^(y)  I*f

—X-alkyl-CP^(x)P^(y)—C_(aa)H_(2aa+1)  I*g

—X-alkyl-C(CH₂P^(v))(CH₂P^(w))—CH₂OCH₂—C(CH₂P^(x))(CH₂Py)CH₂P^(z)  I*h

—X-alkyl-CH((CH₂)_(aa)P^(x))((CH₂)_(bb)P^(y))  I*i

—X-alkyl-CHP^(x)CHP^(y)—C_(aa)H_(2aa+1)  I*k

in which

-   alkyl denotes a single bond or straight-chain or branched alkylene    having 1 to 12 C atoms, in which one or more non-adjacent CH₂ groups    may each be replaced, independently of one another, by    —C(R^(x))═C(R^(x))—, —C═C—, —N(R^(x))—, —O—, —S—, —CO—, —CO—O—,    —O—CO—, —O—CO—O— in such a way that O and/or S atoms are not linked    directly to one another, and in which, in addition, one or more H    atoms may be replaced by F, Cl or CN, where R^(x) has one the    above-mentioned meaning,-   _(aa) and _(bb) each, independently of one another, denote 0, 1, 2,    3, 4, 5 or 6,-   X has one of the meanings indicated for X′, and-   P^(v) to P^(z) each, independently of one another, have one of the    meanings indicated above for P.

Preferred spacer groups Sp are selected from alkylene having 1 to 20,preferably 1 to 12 C atoms, which is optionally mono- or polysubstitutedby F, Cl, Br, I or CN and in which, in addition, one or morenon-adjacent CH₂ groups may each be replaced, independently of oneanother, by —O—, —S—, —NH—, —NR^(xx)—, —SiR^(xx)R^(yy)—, —CO—, —COO—,—OCO—, —OCO—O—, —S—CO—, —CO—S—, —NR^(xx)—CO—O—, —O—CO—NR^(0xx)—,—NR^(xx)—CO—NR^(yy)—, —CH═CH— or —C═C— in such a way that O and/or Satoms are not linked directly to one another, and wherein R^(xx) andR^(yy) each, independently of one another, denote H or alkyl having 1 to12 C atoms.

Further preferred spacer groups Sp are selected from the formula Sp′-X′,so that the radical “P-Sp-” conforms to the formula “P-Sp′-X′—”, where

-   Sp′ denotes alkylene having 1 to 20, preferably 1 to 12 C atoms,    which is optionally mono- or polysubstituted by F, Cl, Br, I or CN    and in which, in addition, one or more non-adjacent CH₂ groups may    each be replaced, independently of one another, by —O—, —S—, —NH—,    —NR^(xx)—, —SiR^(xx)R^(yy)—, —CO—, —COO—, —OCO—, —OCO—O—, —S—CO—,    —CO—S—, —NR^(xx)—CO—O—, —O—CO—NR^(0xx)—, —NR^(xx)—CO—NR^(yy)—,    —CH═CH— or —C═C— in such a way that 0 and/or S atoms are not linked    directly to one another,-   X′ denotes —O—, —S—, —CO—, —COO—, —OCO—, —O—COO—, —CO—NR^(xx)—,    —NR^(xx)—CO—, —NR^(xx)—CO—NR^(yy)—, —OCH₂—, —CH₂O—, —SCH₂—, —CH₂S—,    —CF₂O—, —OCF₂—, —CF₂S—, —SCF₂—, —CF₂CH₂—, —CH₂CF₂—, —CF₂CF₂—,    —CH═N—, —N═CH—, —N═N—, —CH═CR^(xx)—, —CY^(xx)═CY^(xx)—, —C═C—,    —CH═CH—COO—, —OCO—CH═CH— or a single bond,    R^(xx) and R^(yy) each, independently of one another, denote H or    alkyl having 1 to 12 C atoms, and    Y^(xx) and Y^(yy) each, independently of one another, denote H, F,    Cl or CN.    X′ is preferably —O—, —S— —CO—, —COO—, —OCO—, —O—COO—, —CO—NR^(xx)—,    —NR^(xx)—CO—, —NR^(xx)—CO—NR^(yy)— or a single bond.

Typical and preferred spacer groups Sp and/or Sp′ are, for example,—(CH₂)_(p1)—, —(CH₂CH₂O)_(q1)—CH₂CH₂—, —CH₂CH₂—S—CH₂CH₂—,—CH₂CH₂—NH—CH₂CH₂— or —(SiR^(xx)R^(yy)—O)_(p1)—, in which p1 is aninteger from 1 to 12, q1 is an integer from 1 to 3, and R^(xx) andR^(yy) have the above-mentioned meanings.

Particularly preferred groups —X′-Sp′- are —(CH₂)_(p1)—, —O—(CH₂)_(p1)—,—OCO—(CH₂)_(p1)—, —OCOO—(CH₂)_(p1)—, in which p1 is an integer from 1 to12.

Particularly preferred groups Sp and/or Sp′ are, for example, in eachcase straight-chain, methylene, ethylene, propylene, butylene,pentylene, hexylene, heptylene, octylene, nonylene, decylene,undecylene, dodecylene, octadecylene, ethyleneoxyethylene,methyleneoxybutylene, ethylenethioethylene,ethylene-N-methyliminoethylene, 1-methylalkylene, ethenylene,propenylene and butenylene.

The term “chiral” in general is used to describe an object that isnon-superimposable on its mirror image.

“Achiral” (non-chiral) objects are objects that are identical to theirmirror image.

The terms “chiral nematic” and “cholesteric” are used synonymously inthis application, unless explicitly stated otherwise.

Chiral nematic textures or cholesteric liquid crystals (CLC) exhibitselective reflection of circular-polarised light, with the direction ofrotation of the light vector corresponding to the direction of rotationof the cholesteric helix.

The reflection wavelength λ is given by the pitch p of the cholesterichelix and the mean birefringence n of the cholesteric liquid crystal inaccordance with the following equation:

λ=n·p

A CLC medium can be prepared, for example, by doping a nematic LC mediumwith a chiral dopant having a high twisting power. The pitch p of theinduced cholesteric helix is then given by the concentration c and thehelical twisting power HTP of the chiral dopant in accordance with thefollowing equation:

p=(HTP c)⁻¹

It is also possible to use two or more dopants, for example in order tocompensate for the temperature dependence of the HTP of the individualdopants and thus to achieve low temperature dependence of the helixpitch and the reflection wavelength of the CLC medium. For the total HTP(HTP_(total)) holds then approximately the following equation:

HTP _(total)=Σ_(i) c _(i) HTP _(i)

wherein c_(i) is the concentration of each individual dopant and HTP_(i)is the helical twisting power of each individual dopant.

For the present invention,

denote trans-1,4-cyclohexylene, and

denote 1,4-phenylene.

For the present invention the groups —COO— or —CO₂— denote an estergroup of formula

and the groups —OCO—, —O₂C— or —OOC— denote an ester group of formula

A “polymer network” is a network in which all polymer chains areinterconnected to form a single macroscopic entity by many crosslinks.

The polymer network can occur in the following types:

-   -   A graft polymer molecule is a branched polymer molecule in which        one or more the side chains are different, structurally or        configurationally, from the main chain.    -   A star polymer molecule is a branched polymer molecule in which        a single branch point gives rise to multiple linear chains or        arms. If the arms are identical, the star polymer molecule is        said to be regular. If adjacent arms are composed of different        repeating subunits, the star polymer molecule is said to be        variegated.    -   A comb polymer molecule consists of a main chain with two or        more three-way branch points and linear side chains. If the arms        are identical, the comb polymer molecule is said to be regular.    -   A brush polymer molecule consists of a main chain with linear,        unbranched side chains and where one or more of the branch        points has four-way functionality or larger.

Throughout the description and claims of this specification, the words“comprise” and “contain” and variations of the words, for example“comprising” and “comprises”, mean “including but not limited to”, andare not intended to (and do not) exclude other components. On the otherhand, the word “comprise” also encompasses the term “consisting of” butis not limited to it.

Throughout the description and claims of this specification, the words“obtainable” and “obtained” and variations of the words, mean “includingbut not limited to”, and are not intended to (and do not) exclude othercomponents. On the other hand, the word “obtainable” also encompassesthe term “obtained” but is not limited to it.

All concentrations are quoted in percent by weight and relate to therespective mixture as a whole, all temperatures are quoted in degreesCelsius and all temperature differences are quoted in differentialdegrees.

DETAILED DESCRIPTION

Preferred are block copolymers wherein said DP is in the range from atleast 2 as to about 100 or 200, more preferably from 2 to about 10 or20, or 30, even more preferably 2 to 6.

Preferred are block copolymers, wherein said polyfluorooxetane block isan oligomer, a polymer, or a copolymer.

Further preferred are block copolymers, wherein total amount of fluorineatoms in each R_(f) or R_(f*) group is generally at least 10% or 25%,desirably at least 50% or 75%, and preferably at least 80%, 85%, 90%, or95%, or even 100% (perfluorinated) of the non-carbon atoms such astrifluoro methyl, pentafluoro ethyl, heptafluoro propyl, etc and of withany remaining non-carbon atoms or nonfluorine atoms being H, or I, or Clor Br.

The pendant or side chain groups R_(f) or R_(f*) can be present on allthe monomers comprising the polymer or on a selected few with apreferable range of about 50 to 100% of monomers comprising the polymercontaining a pendant or side chain groups R_(f) or R_(f*).

A preferred polymer contains one R_(f) group and no group R_(f)* perrepeat unit. Therefore, the following repeat unit is preferred

Preferably n denotes an integer from 1 to 6, preferably 1, 2, 3 or 4.

R_(f) denotes independently on each monomer a linear or branched,unsaturated, or preferably saturated alkyl group of 1 to about 7, orabout 10, or about 15, or about 20 carbon atoms with a minimum of 25,50, 75, 80, 85, 90 or 95, or preferably perfluorinated i.e. 100 percentof the H atoms of said R_(f) being replaced by F, and optionally up toall of the remaining H atoms being replaced by I, Cl or Br.

When R_(f) is a short chain, it preferably contains 1, 2, 3, or 4 carbonatoms. R_(f) can either contain a linear alkyl group or a branched alkylgroup, preferably a linear alkyl group.

When it is a branched group, the main chain contains from 1 to 7 carbonatoms and each branch chain can contain up to 3 carbon atoms as well.

R is hydrogen, or an alkyl from 1 to 6 carbon atoms with methyl or ethylbeing preferred, more preferably methyl.

Suitable polyethers include hydroxyl terminated polyethylene glycol,polypropylene glycol, polybutylene glycol, polyisobutylene glycol, andthe like as well as monohydroxyl compounds thereof such as polyethyleneglycol methyl ether, polytetrahydrofuran, and the like. Preferably thepolyether is neopentyl glycol.

The average molecular weight of such polyethers is generally from about50 to about 10,000, desirably from about 75 to about 5,000 andpreferably from about 100 to about 2,500 and can thus be an monomer,oligomer, polymer or copolymer.

Preferably the block copolymer is an AB, or a BAB, or a BA, or an ABAblock copolymer, wherein said A block is said polyether block and said Bblock is said polyfluorooxetane block.

Block copolymers of polyfluorooxetanes and polyethers can be preparedaccording to two different routes. In one route, a polyether serves asan initiator which is reacted with fluorooxetane monomers; oralternatively, fluorooxetane oligomers, polymers, or copolymers serve asan initiator which is reacted with alkylene oxide monomers, in thepresence of a catalyst to form polyfluorooxetane blocks which are bondedor connected to the polyether, or alternatively to form polyether blockswhich are connected to the fluorooxetane oligomer, polymer, orcopolymer.

The polyether which serves as an initiator can be made in a manner knownto the literature as well as to the art. One common source are alkyleneoxide monomers containing from 2 to about 6 carbon atoms and preferablyfrom 2 to about 4 carbon atoms.

The fluorooxetane monomers are those as set forth in 2003/0109662 A1,which is hereby fully incorporated by reference.

Polymerization of the one or more fluorooxetane monomers which isinitiated by the one or more polyether functional groups such as ahydroxyl is desirably carried out via solution polymerization and thusis polymerized in the presence of a solvent. Suitable solvents aregenerally polar and/or halogenated hydrocarbons having a total from 1 toabout 6 carbon atoms such as methylene chloride, carbon tetrachloride,chloroform, trichloroethylene, chlorobenzene, ethyl bromide,dichloroethane, and the like, with methylene chloride being preferred.

The amount of such solvents is generally from about 50 to about 100 anddesirably from about 50 to about 65 parts by weight for every 100 partsby weight of the polyether initiator and the total weight of the one ormore fluorooxetane monomers.

The one or more fluorooxetane monomers which are polymerized onto thepolyether initiator having 1 or more functional groups such as ahydroxyl readily polymerize in the presence of the Lewis acid catalyst(ire. compounds capable of accepting a pair of electrons). Such suitableLewis acids include complexes of boron trifluoride, for example BF₃etherate, BF₃-THF, antimony pentafluoride, zinc chloride, aluminumbromide, and the like with BF₃-THF being preferred. When BF₃-THF isutilized, the THF will be polymerized and hence a fluorooxetane-THFcopolymer will be produced. Generally the amount of THF within thecopolymer is from about 0.05 to about 10 or about 12 or about 30 orabout 50 percent by weight and desirably from about 0.1 to about 5percent by weight based upon the total weight of the copolymer.

Polymerization is carried out at temperatures of from about 15° C. to 1or 2 degrees below the boiling point of the solvent, desirably fromabout 25° C. to about 45° C., and preferably from about 35° C. to about40° C. Polymerization times can vary with regard to the temperature andother factors and generally range from about 1% to about 5 hours. Oncethe various fluorooxetane monomers have been polymerized onto thepolyether, the end product which is a block copolymer can be washed withwater to remove the solvent.

If the polyether initiator has one functional end group such as ahydroxyl, an AB block copolymer will be formed wherein the B block isderived from the fluorooxetane monomers and the A block is derived fromthe monohydroxyl polyether. Alternatively, if the polyether has twofunctional end groups, a BAB block copolymer will be formed. In eithersituation, the B block will have a hydroxyl end group.

Including a block copolymer as described above and below in apolymerizable LC material allows easy formation of an aligned CLC phasewith no visible haze while also allowing another layer to be coated ontop which gives good alignment without the need for a second alignmentlayer.

Choosing this block copolymer type also does not have any problems withdewetting of the upper layer in a layer stack, which is common whenusing surfactant additives.

The concentration of block copolymers as described above and below inthe polymerizable LC material is preferably from 0.01% to 1%, morepreferably from 0.03% to 0.7%, especially from 0.05% to 0.5%.

The block copolymers as described above and below can advantageously andpreferably be prepared in accordance with the disclosure given in US2003/0109662 A1 or are commercially available as additives of thePolyFox® series available from Omnova Solutions Inc., USA, such as forexample PolyFox® PF-636, PolyFox® PF-6320, PolyFox® PF-656, PolyFox®PF-650, or Polyfox® PF-7002:

In a preferred embodiment, the polymerizable LC material comprises oneor more reactive mesogens selected from formula RMT,

-   P is a polymerizable group,-   Sp is a spacer group or a single bond,-   r2 and r3 are independently of each other 0, 1, 2, 3 or 4,-   R¹¹ is P-Sp-, alkyl, alkoxy, thioalkyl, alkylcarbonyl,    alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy preferably    with 1 to 15 C atoms, which is more preferably optionally    fluorinated.-   A and B denote, in case of multiple occurrence independently of one    another, an aromatic or alicyclic group, which optionally contains    one or more heteroatoms selected from N, O and S, and is optionally    mono- or polysubstituted by L, preferably 1,4-phenylene,    pyridine-2,5-diyl, pyrimidine-2,5-diyl, thiophene-2,5-diyl,    naphthalene-2,6-diyl, 1,2,3,4-tetrahydro-naphthalene-2,6-diyl,    indane-2,5-diyl, bicyclooctylene or 1,4-cyclohexylene wherein one or    two non-adjacent CH₂ groups are optionally replaced by 0 and/or S,    wherein these groups are unsubstituted or substituted by 1, 2, 3 or    4 groups L-   L is P-Sp-, F, Cl, Br, I, —CN, —NO₂, —NCO, —NCS, —OCN, —SCN,    —C(═O)NR^(x)R^(y), —C(═O)OR^(x), —C(═O)R^(x), —NR^(x)R^(y), —OH,    —SF5, or straight chain or branched alkyl, alkoxy, alkylcarbonyl,    alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 12 C    atoms, wherein one or more H atoms are optionally replaced by F or    Cl, preferably F, —CN or straight chain or branched alkyl, alkoxy,    alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy    with 1 to 6 C atoms,-   R^(x) and R^(y) independently of each other denote H or alkyl with 1    to 12 C-atoms,-   Z¹¹ and Z¹² denotes, in case of multiple occurrence independently of    one another, —O—, —S—, —CO—, —COO—, —OCO—, —S—CO—, —CO—S—, —O—COO—,    —CO—NR⁰⁰—, —NR⁰⁰—CO—, —NR⁰⁰—CO—NR⁰⁰⁰, —NR⁰⁰—CO—O—, —O—CO—NR⁰⁰—,    —OCH₂—, —CH₂O—, —SCH₂—, —CH₂S—, —CF₂O—, —OCF₂—, —CF₂S—, —SCF₂—,    —CH₂CH₂—, —(CH₂)_(n1), —CF₂CH₂—, —CH₂CF₂—, —CF₂CF₂—, —CH═N—, —N═CH—,    —N═N—, —CH═CR⁰⁰—, —CY¹═CY²—, —C═C—, —CH═CH—COO—, —OCO—CH═CH— or a    single bond, preferably —COO—, —OCO—, —C═C—, or a single bond,-   Y¹ and Y² independently of each other denote H, F, C or CN,-   n is 1, 2, 3 or 4, preferably 1 or 2, most preferably 1,-   m is 0, 1, 2, 3 or 4, preferably 0 or 1, most preferably 0, and-   n1 is an integer from 1 to 10, preferably 1, 2, 3 or 4.

Preferred compounds of formula RMT are those selected of formula RMTa orRMTb,

wherein

-   P is a polymerizable group,-   Sp is a spacer group or a single bond,-   r1, r2, r3 are independently of each other 0, 1, 2, 3 or 4,    preferably 0, 1 or 2 and-   L, R¹¹, Z¹², ring B and m have one of the meanings as given above    under formula RMT.

Preferred compounds of formula RMTa are those selected of formula RMTa1to RMTa6

wherein L, P, Sp, and R¹¹ are as defined in formula RMT, r1 to r3denotes 1, 2, 3, or 4, preferably 1 or 2.

Preferred compounds of formula RMTa1 to RMTa6 are selected of thefollowing formulae

Wherein P¹¹ denotes selected from the group consisting of heptadiene,vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate,oxetane and epoxide groups, and very preferably denotes an acrylate,methacrylate or oxetane group, especially an acrylate or methacrylategroup, in particular an acrylate group, and x is an integer from 0 to12, preferably from 1 to 8, more preferably 3, 4, 5 or 6, in particularx denotes 3 or 6, especially 6 and R¹¹ denotes alkyl, alkoxy,alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxypreferably with 1 to 15 C atoms which is more preferably optionallyfluorinated and L has on each occurrence one of the meanings as givenabove under formula RMT.

Especially preferred are the compounds of formula RMTa2, which arepreferably selected from the following formulae:

Wherein R¹¹ has one of the meanings as given above under formula RMT,preferably R¹¹ denotes alkyl or alkoxy, more preferably, methoxy,ethoxy, propoxy, methyl, ethyl, propyl, butyl, pentyl, isopropyl orisobutyl, in particular methoxy.

Preferred compounds of formula RMTb are those selected of formula RMTb0to RMTb6

wherein L, P, Sp, and R¹¹ are as defined in formula RMT, r1 to r3denotes 1, 2, 3, or 4, preferably 1 or 2.

Preferred compounds of formula RMTb0 to RMTb6 are selected of thefollowing formulae

Wherein P¹¹ denotes selected from the group consisting of heptadiene,vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate,oxetane and epoxide groups, and very preferably denotes an acrylate,methacrylate or oxetane group, especially an acrylate or methacrylate 15group, in particular an acrylate group, and x is an integer from 0 to12, preferably from 1 to 8, more preferably 3, 4, 5 or 6, in particularx denotes 3 or 6, especially 6 and R¹¹ denotes alkyl, alkoxy,alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxypreferably with 1 to 15 C atoms which is more preferably optionallyfluorinated and L has on each occurrence one of the meanings as givenabove under formula RMT.

Especially preferred are the compounds of formula RMTb2, which arepreferably selected from the following formulae:

Wherein R¹¹ has one of the meanings as given above under formula RMT.Preferably, R¹¹ denotes alkyl or alkoxy.

Further preferred are compounds of formula RMTb2-A1, which are selectedfrom compounds of the following formulae

Wherein R¹¹ has one of the meanings as given above under formula RMT,preferably R¹¹ denotes alkyl or alkoxy, more preferably, methoxy,ethoxy, propoxy, methyl, ethyl, propyl, butyl, pentyl, isopropyl orisobutyl, in particular methoxy.

Preferably, the polymerizable LC material comprises one or more,preferably two or more compounds selected from formulae RMTa2-A3 toRMTa2-A6 or RMTb2-A3, especially the polymerizable LC material comprisesone or more compounds of formula RMTb2-A3, in particular, thepolymerizable LC material comprises a combination of compounds offormulae RMTa2-A4 and/or RMTa2-A5 with RMTb2-A3.

By utilizing one or more compounds of formula RMT in the polymerizableLC materials, the birefringence of a polymer film can be beneficiallyincreased.

The corresponding reflection bandwidth is related to birefringence bythe following formula:

Bandwidth=Δn*pitch,

it can be seen that by increasing the birefringence of the cholestericpolymer film, it is possible to achieve a wider bandwidth of reflection.By utilizing compounds of formula RMT in a polymerizable LC material, itis possible to widen the reflection bandwidth significantly of acorresponding polymer film while also not negatively affecting filmproperties such as wet film crystallization or dewetting.

The concentration of compounds of formula RMT and its subformulae, inthe polymerizable LC material is preferably from 40% to 99%, morepreferably from 45 to 95%, especially from 50 to 90%.

The compounds of formula RMT are either commercially available fromMerck KGaA, Darmstadt or can be synthesized in accordance with theprocedures given for example in U.S. Pat. No. 6,514,578 or U.S. Ser. No.15/575,415.

In preferred embodiment, the polymerizable LC material comprises one ormore di- or multireactive reactive mesogens that are preferably selectedof formula DRM

P¹-Sp¹-MG-Sp²-P²  DRM

wherein

-   P¹ and P² independently of each other denote a polymerizable group,-   Sp¹ and Sp² independently of each other are a spacer group or a    single bond, and-   MG is a rod-shaped mesogenic group, which is preferably selected of    formula MG

-(A¹-Z¹)_(n)-A²-  MG

wherein

-   A¹ and A² denote, in case of multiple occurrence independently of    one another, an aromatic or alicyclic group, which optionally    contains one or more heteroatoms selected from N, O and S, and is    optionally mono- or polysubstituted by L,-   L is P-Sp-, F, Cl, Br, I, —CN, —NO₂, —NCO, —NCS, —OCN, —SCN,    —C(═O)NR^(x)R^(y), —C(═O)OR^(x), —C(═O)R^(x), —NR^(x)R^(y), —OH,    —SF₅, optionally substituted silyl, aryl or heteroaryl with 1 to 12,    preferably 1 to 6 C atoms, and straight chain or branched alkyl,    alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or    alkoxycarbonyloxy with 1 to 12, preferably 1 to 6 C atoms, wherein    one or more H atoms are optionally replaced by F or Cl,-   R^(x) and R^(y) independently of each other denote H or alkyl with 1    to 12 C-atoms,-   Z¹ denotes, in case of multiple occurrence independently of one    another, —O—, —S—, —CO—, —COO—, —OCO—, —S—CO—, —CO—S—, —O—COO—,    —CO—NR^(x)—, —NR^(x)—CO—, —NR^(x)—CO—NR^(y), —NR^(x)—CO—O—,    —O—CO—NR^(x)—, —OCH₂—, —CH₂O—, —SCH₂—, —CH₂S—, —CF₂O—, —OCF₂—,    —CF₂S—, —SCF₂—, —(CH₂)_(n1), —CF₂CH₂—, —CH₂CF₂—, —CF₂CF₂—, —CH═N—,    —N═CH—, —N═N—, —CH═CR^(x)—, —CY¹=CY²—, —C≡C—, —CH═CH—COO—,    —OCO—CH═CH— or a single bond, preferably —COO—, —OCO— or a single    bond,-   Y¹ and Y² independently of each other denote H, F, Cl or CN,-   n is 1, 2, 3 or 4, preferably 1 or 2, most preferably 2, n1 is an    integer from 1 to 10, preferably 1, 2, 3 or 4, however, under the    condition that compounds of formula RMT are excluded from the    compounds of formula DRM.

Preferred groups A¹ and A² include, without limitation, furan, pyrrol,thiophene, oxazole, thiazole, thiadiazole, imidazole, phenylene,cyclohexylene, bicyclooctylene, cyclohexenylene, pyridine, pyrimidine,pyrazine, azulene, indane, fluorene, naphthalene, tetrahydronaphthalene,anthracene, phenanthrene and dithienothiophene, all of which areunsubstituted or substituted by 1, 2, 3 or 4 groups L as defined above.

Particular preferred groups A¹ and A² are selected from 1,4-phenylene,pyridine-2,5-diyl, pyrimidine-2,5-diyl, thiophene-2,5-diyl,naphthalene-2,6-diyl, 1,2,3,4-tetrahydro-naphthalene-2,6-diyl,indane-2,5-diyl, bicyclooctylene or 1,4-cyclohexylene wherein one or twonon-adjacent CH₂ groups are optionally replaced by O and/or S, whereinthese groups are unsubstituted or substituted by 1, 2, 3 or 4 groups Las defined above.

Preferred RMs of formula DRM are selected of formula DRMa

wherein

-   P⁰ is, in case of multiple occurrence independently of one another,    a polymerizable group, preferably an acryl, methacryl, oxetane,    epoxy, vinyl, heptadiene, vinyloxy, propenyl ether or styrene group,-   Z⁰ is —COO—, —OCO—, —CH₂CH₂—, —CF₂O—, —OCF₂—, —C≡C—, —CH═CH—,    —OCO—CH═CH—, —CH═CH—COO—, or a single bond,-   L has on each occurrence identically or differently one of the    meanings given for L in formula DRM, and is preferably, in case of    multiple occurrence independently of one another, selected from F,    Cl, CN or optionally halogenated alkyl, alkoxy, alkylcarbonyl,    alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 5 C    atoms,-   r is 0, 1, 2, 3 or 4,-   x and y are independently of each other 0 or identical or different    integers from 1 to 12,-   z is 0 or 1, with z being 0 if the adjacent x or y is 0.

Very preferred RMs of formula DRM are selected from the followingformulae:

-   wherein P°, L, r, x, y and z are as defined in formula DRMa.

Especially preferred are compounds of formula DRMa1, DRMa2 and DRMa3, inparticular those of formula DRMa1.

The concentration of di- or multireactive RMs, preferably those offormula DRM and its subformulae, in the RM mixture is preferably from 1%to 60%, very preferably from 5 to 40%.

In another preferred embodiment, the RM mixture comprises one or moremonoreactive RMs. These additional monoreactive RMs are preferablyselected from formula MRM:

P¹—Sp¹-MG-R  MRM

wherein P¹, Sp¹ and MG have the meanings given in formula DRM,

-   R denotes P-Sp-, F, Cl, Br, I, —CN, —NO₂, —NCO, —NCS, —OCN, —SCN,    —C(═O)NR^(x)R^(y), —C(═O)X, —C(═O)OR^(x), —C(═O)R^(y), —NR^(x)R^(y),    —OH, —SF₅, optionally substituted silyl, straight chain or branched    alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or    alkoxycarbonyloxy with 1 to 12, preferably 1 to 6 C atoms, wherein    one or more H atoms are optionally replaced by F or Cl,-   X is halogen, preferably F or Cl, and-   R^(x) and R^(y) are independently of each other H or alkyl with 1 to    12 C-atoms, however, under the condition that compounds of formula    RMT are excluded from the compound of formula MRM.

Preferably, the compounds of formula MRM are selected from the followingformulae.

wherein P⁰, L, r, x, y and z are as defined in formula DRMa,

-   R^(D) is alkyl, alkoxy, thioalkyl, alkylcarbonyl, alkoxycarbonyl,    alkylcarbonyloxy or alkoxycarbonyloxy with 1 or more, preferably 1    to 15 C atoms or denotes Y⁰ or P—(CH₂)_(y)—(O)_(z)—,-   X⁰ is —O—, —S—, —CO—, —COO—, —OCO—, —O—COO—, —CO—NR⁰¹—, —NR⁰¹—CO—,    —NR⁰¹—CO—NR⁰¹—, —OCH₂—, —CH₂O—, —SCH₂—, —CH₂S—, —CF₂O—, —OCF₂—,    —CF₂S—, —SCF₂—, —CF₂CH₂—, —CH₂CF₂—, —CF₂CF₂—, —CH═N—, —N═CH—, —N═N—,    —CH═CR⁰¹—, —CF═CF—, —C≡C—, —CH═CH—COO—, —OCO—CH═CH— or a single bond-   Y⁰ is F, Cl, CN, NO₂, OCH₃, ON, SON, SF₅, or mono- oligo- or    polyfluorinated alkyl or alkoxy with 1 to 4 atoms,-   Z⁰ is —COO—, —OCO—, —CH₂CH₂—, —CF₂O—, —OCF₂—, —CH═CH—, —OCO—    —CH═CH—, —CH═CH—COO—, or a single bond,-   A⁰ is, in case of multiple occurrence independently of one another,    1,4-phenylene that is unsubstituted or substituted with 1, 2, 3 or 4    groups L, or trans-1,4-cyclohexylene,-   R^(01,02) are independently of each other H, R⁰ or Y⁰,-   u and v are independently of each other 0, 1 or 2,-   w is 0 or 1,    and wherein the benzene and naphthalene rings can additionally be    substituted with one or more identical or different groups L.

Especially preferred are compounds of formula MRM1, MRM2, MRM3, MRM4,MRM5, MRM6, MRM7, in particular those of formula MRM1, MRM4, MRM6, andMRM7.

The concentration of all monoreactive RMs, including those of formulaRMT, in the polymerizable LC material is preferably from 1 to 80%, verypreferably from 5 to 20%.

In formulae DRM, MRM and their preferred subformulae, L is preferablyselected from F, Cl, CN, NO₂ or straight chain or branched alkyl,alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonlyoxy oralkoxycarbonyloxy with 1 to 12 C atoms, wherein the alkyl groups areoptionally perfluorinated, or P-Sp-.

Very preferably L is selected from F, Cl, CN, NO₂, CH₃, C₂H₅, C(CH₃)₃,CH(CH₃)₂, CH₂CH(CH₃)C₂H₅, OCH₃, OC₂H₅, COCH₃, COC₂H₅, COOCH₃, COOC₂H₅,CF₃, OCF₃, OCHF₂, OC₂F₅ or P-Sp-, in particular F, Cl, CN, CH₃, C₂H₅,C(CH₃)₃, CH(CH₃)₂, OCH₃, COCH₃ or OCF₃, most preferably F, Cl, CH₃,C(CH₃)₃, OCH₃ or COCH₃, or P-Sp-.

Preferably, the polymerizable LC material according to the presentinvention comprises one or more chiral compounds. These chiral compoundsmay be non-mesogenic compounds or mesogenic compounds. Additionally,these chiral compounds, whether mesogenic or non-mesogenic, may benon-reactive, monoreactive or multireactive.

Preferably the utilized chiral compounds have each alone or incombination with each other an absolute value of the helical twistingpower (IHTP_(total)) of 20 μm⁻¹ or more, preferably of 40 μm⁻¹ or more,more preferably in the range of 60 μm⁻¹ or more, most preferably in therange of 80 μm⁻¹ or more to 260 μm⁻¹, in particular those disclosed inWO 98/00428.

Preferably, non-polymerizable chiral compounds are selected from thegroup of compounds of formulae C-I to C-III,

the latter ones including the respective (S,S) enantiomers,wherein E and F are each independently 1,4-phenylene ortrans-1,4-cyclohexylene, v is 0 or 1, Z⁰ is —COO—, —OCO—, —CH₂CH₂— or asingle bond, and R is alkyl, alkoxy or alkanoyl with 1 to 12 C atoms.

Particularly preferred polymerizable LC materials that comprise one ormore chiral compounds, which do not necessarily have to show a liquidcrystalline phase.

The compounds of formula C—II and their synthesis are described in WO98/00428. Especially preferred is the compound CD-1, as shown in table Dbelow. The compounds of formula C—III and their synthesis are describedin GB 2 328 207.

Further, typically used chiral compounds are e.g. the commerciallyavailable R/S-5011, CD-1, R/S-811 and CB-15 (from Merck KGaA, Darmstadt,Germany).

The above mentioned chiral compounds R/S-5011 and CD-1 and the (other)compounds of formulae C-I, C-II and C-III exhibit a very high helicaltwisting power (HTP), and are therefore particularly useful for thepurpose of the present invention.

The polymerizable LC material preferably comprises 1 to 5, in particular1 to 3, very preferably 1 or 2 chiral compounds, preferably selectedfrom the above formula C-II, in particular CD-1, and/or formula C-IIIand/or R-5011 or S-5011, very preferably, the chiral compound is R-5011,S-5011 or CD-1.

Preferably, the polymerizable LC material comprise one or morenon-reactive chiral compound and/or one or more reactive chiralcompounds, which are preferably selected from mono- and/or multireactivechiral compounds.

Suitable mesogenic reactive chiral compounds preferably comprise one ormore ring elements, linked together by a direct bond or via a linkinggroup and, where two of these ring elements optionally may be linked toeach other, either directly or via a linking group, which may beidentical to or different from the linking group mentioned. The ringelements are preferably selected from the group of four-, five-, six- orseven-, preferably of five- or six-, membered rings.

Preferred mono-reactive chiral compounds are selected from compounds offormula CRMa to CRMc,

wherein

-   P^(0*) denotes a polymerizable group P-   Sp* denotes a spacer Sp-   A⁰ and B⁰ are, in case of multiple occurrence independently of one    another, 1,4-phenylene that is unsubstituted or substituted with 1,    2, 3 or 4 groups L as defined above, or trans-1,4-cyclohexylene,-   X¹ and X² are independently of each other —O—, —COO—, —OCO—,    —O—CO—O— or a single bond,-   Z^(0*) is, in case of multiple occurrence independently of one    another, —COO—, —OCO—, —O—CO—O—, —OCH₂—, —CH₂O—, —CF₂O—, —OCF₂—,    —CH₂CH₂—, —(CH₂)₄—, —CF₂CH₂—, —CH₂CF₂—, —CF₂CF₂—, —C≡C—, —CH═CH—,    —CH═CH—COO—, —OCO—CH═CH— or a single bond,-   t is, independently of each other 0, 1, 2 or 3,-   a is 0, 1 or 2,-   b is 0 or an integer from 1 to 12,-   z is 0 or 1,    and wherein the naphthalene rings in formula CRMa can additionally    be substituted with one or more identical or different groups L    wherein-   L is, independently of each other F, Cl, CN, halogenated alkyl,    alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or    alkoxycarbonyloxy with 1 to 5 C atoms.

The compounds of formula CRMa are preferably selected from the group ofcompounds of formulae CRMa-1.

wherein X², A⁰, B⁰, Z^(0*), P^(0*) and b have the meanings given informula CRMa or one of the preferred meanings given above and below, and(OCO) denotes —O—CO— or a single bond.

Especially preferred compounds of formula CRM are selected from thegroup consisting of the following subformulae:

wherein R is —X²—(CH₂)_(x)—P^(0*) as defined in formula CRM-a, and thebenzene and naphthalene rings are unsubstituted or substituted with 1,2, 3 or 4 groups L as defined above and below.

The compounds of formula CRMb are preferably selected from the group ofcompounds of formulae CRMb-1 to CRMb-3,

wherein X², A⁰, B°, Z⁰*, P^(0*) and b have the meanings given in formulaCRMa or one of the preferred meanings given above and below.

Preferred compounds of formula CRMb-1 are preferably selected from thegroup of compounds of formulae CRMb-1a and CRMb-1 b,

wherein X², Z^(0*), P^(0*) and b have the meanings given in formula CRMaor one of the preferred meanings given above and below. Preferably, inthe compounds of formulae CRMb-1a and CRMb-1b, Z⁰ denotes OCOO, COO, OCOor a single bond. Preferably, in the compounds of formulae CRMb-1a andCRMb-1b, X² denotes OCOO, OCO, COO or a single bond. Preferred arecompounds of formula and CRMb-1 b that are selected from the followingcompounds,

wherein P^(0*) and b have the meanings given in formula CRMa or one ofthe preferred meanings given above and below.

The compound CRMb-1 bl wherein P^(0*) denotes in each occurrence anacrylate group and b denotes in each occurrence 4, is especiallypreferred and commercially available from BASF, Germany under tradenameLC756.

The compounds of formula CRMc are preferably selected from the group ofcompounds of formulae CRMc-1,

wherein X², A⁰, B⁰, Z^(0*), P^(0*) and b have the meanings given informula CRMa or one of the preferred meanings given above and below.

Preferred compounds of formula CRMc-1 are preferably selected from thegroup of compounds of formulae CRMc-1a and CRMc-1 b,

wherein X², Z^(0*), P^(0*) and b have the meanings given in formula CRMaor one of the preferred meanings given above and below. Preferably, inthe compounds of formulae CRMc-1a and CRMc-1b, Z⁰ denotes OCOO, COO, OCOor a single bond. Preferably, in the compounds of formulae CRMc-1a andCRMc-1 b, X² denotes O, OCOO, OCO, COO or a single bond.

Preferred are compounds of formula and CRMc-1a that are selected fromthe following compounds,

wherein P^(0*) and b have the meanings given in formula CRMa or one ofthe preferred meanings given above and below.

The compound CRMc-1al wherein P*denotes in each occurrence an acrylategroup and b denotes in each occurrence 3 or 6, and X² denotes in eachoccurrence O or a single bond is especially preferred.

The amount of chiral compounds in the liquid-crystalline medium ispreferably from 1 to 20%, more preferably from 1 to 15%, even morepreferably 1 to 10%, and most preferably 3 to 7%, by weight of the totalmixture.

In a preferred embodiment, the proportion of polymerizable mesogeniccompounds in the polymerizable liquid-crystalline material, according tothe present invention as a whole, is in the range from 30 to 99% byweight, more preferably in the range from 40 to 97% by weight and evenmore preferably in the range from 50 to 95% by weight.

Preferably, the proportion of said mono-, di- or multireactiveliquid-crystalline compounds, preferably selected from the compounds ofthe formulae DRM, MRM as given above and below in the polymerizableliquid-crystalline material according to the present invention as awhole, is preferably in the range from 30 to 99.9% by weight, morepreferably in the range from 40 to 99.9% by weight and even morepreferably in the range from 50 to 99.9% by weight.

In a preferred embodiment, the proportion of di- or multireactivepolymerizable mesogenic compounds in the polymerizableliquid-crystalline material according to the present invention as awhole, is preferably in the range from 1 to 70% by weight, morepreferably in the range from 2 to 60% by weight and even more preferablyin the range from 3 to 50% by weight.

In another preferred embodiment, the proportion of monoreactivepolymerizable mesogenic compounds of formula MRM excluding compounds offormula RMT in a polymerizable liquid-crystalline material according tothe present invention as a whole, is, if present, preferably in therange from 1 to 50% by weight, more preferably in the range from 2 to45% by weight and even more preferably in the range from 5 to 40% byweight.

In another preferred embodiment, the proportion of multireactivepolymerizable mesogenic compounds in a polymerizable liquid-crystallinematerial according to the present invention as a whole is, if present,preferably in the range from 1 to 30% by weight, more preferably in therange from 2 to 20% by weight and even more preferably in the range from3 to 10% by weight.

In another preferred embodiment the polymerizable LC material does notcontain polymerizable mesogenic compounds having more than twopolymerizable groups.

In a further preferred embodiment, the polymerizable LC materialcomprises one or more monoreactive mesogenic compounds, preferablyselected from formulae MRM-1, MRM-4, MRM-6, and/or MRM-7, one or moredireactive mesogenic compounds, preferably selected from formula DRMa-1.

The polymerizable LC material should in addition be of such a naturethat different reflection wavelengths, in particular in the VIS lightregion, can be achieved by simple and targeted variation. Preferably thecholesteric pitch of the polymerizable LC material is selected such,that their wavelength of reflection is in the in the range in theinfrared range of the electromagnetic spectrum i.e. in the range from of300 nm to 900 nm, more preferably form 350 to 850 nm. In particular, thereflection wavelength of the liquid crystalline medium is in the rangeof 400 nm to 800 nm.

The polymerizable LC material according to the present invention areprepared in a manner conventional per se, for example by mixing one ormore of the above-mentioned polymerizable compounds with one or moreblock copolymers as described above and below, and one or more chiralcompounds, both as defined above, and optionally with furtherliquid-crystalline compounds and/or additives, and/or solvents.

In a further preferred embodiment the polymerizable LC materialoptionally comprises one or more additives selected from the groupconsisting of further polymerization initiators, antioxidants,surfactants, stabilisers, catalysts, sensitizers, inhibitors,chain-transfer agents, co-reacting monomers, reactive thinners,surface-active compounds, lubricating agents, wetting agents, dispersingagents, hydrophobing agents, adhesive agents, flow improvers, degassingor defoaming agents, deaerators, diluents, reactive diluents,auxiliaries, colourants, dyes, pigments and nanoparticles.

In another preferred embodiment, the polymerizable LC materialoptionally comprises one or more additives selected from polymerizablenon-mesogenic compounds (reactive thinners). The amount of theseadditives in the polymerizable LC material is preferably from 0 to 30%,very preferably from 0 to 25%.

The reactive thinners used are not only substances which are referred toin the actual sense as reactive thinners, but also auxiliary compoundsalready mentioned above which contain one or more complementary reactiveunits or polymerizable groups P, for example hydroxyl, thiol-, or aminogroups, via which a reaction with the polymerizable units of theliquid-crystalline compounds can take place.

The substances, which are usually capable of photopolymerization,include, for example, mono-, bi- and polyfunctional compounds containingat least one olefinic double bond. Examples thereof are vinyl esters ofcarboxylic acids, for example of lauric, myristic, palmitic and stearicacid, and of dicarboxylic acids, for example of succinic acid, adipicacid, allyl and vinyl ethers and methacrylic and acrylic esters ofmonofunctional alcohols, for example of lauryl, myristyl, palmityl andstearyl alcohol, and diallyl and divinyl ethers of bifunctionalalcohols, for example ethylene glycol and 1,4-butanediol.

Also suitable are, for example, methacrylic and acrylic esters ofpolyfunctional alcohols, in particular those that contain no furtherfunctional groups, or at most ether groups, besides the hydroxyl groups.Examples of such alcohols are bifunctional alcohols, such as ethyleneglycol, propylene glycol and their more highly condensedrepresentatives, for example diethylene glycol, triethylene glycol,dipropylene glycol, tripropylene glycol etc., butanediol, pentanediol,hexanediol, neopentyl glycol, alkoxylated phenolic compounds, such asethoxylated and propoxylated bisphenols, cyclohexanedimethanol,trifunctional and polyfunctional alcohols, such as glycerol,trimethylolpropane, butanetriol, trimethylolethane, pentaerythritol,ditrimethylolpropane, dipentaerythritol, sorbitol, mannitol, and thecorresponding alkoxylated, in particular ethoxylated and propoxylatedalcohols.

Other suitable reactive thinners are polyester (meth)acrylates, whichare the (meth)acrylic ester of polyesterols.

Examples of suitable polyesterols are those that can be prepared byesterification of polycarboxylic acids, preferably dicarboxylic acids,using polyols, preferably diols. The starting materials for suchhydroxyl-containing polyesters are known to the person skilled in theart. Dicarboxylic acids which can be employed are succinic, glutaricacid, adipic acid, sebacic acid, o-phthalic acid and isomers andhydrogenation products thereof, and esterifiable and transesterifiablederivatives of said acids, for example anhydrides and dialkyl esters.Suitable polyols are the abovementioned alcohols, preferablyethyleneglycol, 1,2- and 1,3-propylene glycol, 1,4-butanediol,1,6-hexanediol, neopentyl glycol, cyclohexanedimethanol and polyglycolsof the ethylene glycol and propylene glycol type.

Suitable reactive thinners are furthermore 1,4-divinylbenzene, triallylcyanurate, acrylic esters of tricyclodecenyl alcohol of the followingformula

also known under the name dihydrodicyclopentadienyl acrylate, and theallyl esters of acrylic acid, methacrylic acid and cyanoacrylic acid.

Of the reactive thinners, which are mentioned by way of example, thosecontaining photopolymerizable groups are used in particular and in viewof the abovementioned preferred compositions.

This group includes, for example, dihydric and polyhydric alcohols, forexample ethylene glycol, propylene glycol and more highly condensedrepresentatives thereof, for example diethylene glycol, triethyleneglycol, dipropylene glycol, tripropylene glycol etc., butanediol,pentanediol, hexanediol, neopentyl glycol, cyclohexanedimethanol,glycerol, trimethylolpropane, butanetriol, trimethylolethane,pentaerythritol, ditrimethylolpropane, dipentaerythritol, sorbitol,mannitol and the corresponding alkoxylated, in particular ethoxylatedand propoxylated alcohols.

The group furthermore also includes, for example, alkoxylated phenoliccompounds, for example ethoxylated and propoxylated bisphenols.

These reactive thinners may furthermore be, for example, epoxide orurethane (meth)acrylates.

Epoxide (meth)acrylates are, for example, those as obtainable by thereaction, known to the person skilled in the art, of epoxidized olefinsor poly- or diglycidyl ether, such as bisphenol A diglycidyl ether, with(meth)acrylic acid.

Urethane (meth)acrylates are, in particular, the products of a reaction,likewise known to the person skilled in the art, of hydroxylalkyl(meth)acrylates with poly- or diisocyanates.

Such epoxide and urethane (meth)acrylates are included amongst thecompounds listed above as “mixed forms”.

If reactive thinners are used, their amount and properties must bematched to the respective conditions in such a way that, on the onehand, a satisfactory desired effect, for example the desired colour ofthe composition according to the invention, is achieved, but, on theother hand, the phase behaviour of the liquid-crystalline composition isnot excessively impaired. The low-crosslinking (high-crosslinking)liquid-crystalline compositions can be prepared, for example, usingcorresponding reactive thinners, which have a relatively low (high)number of reactive units per molecule.

The group of diluents include, for example:

C₁-C₄-alcohols, for example methanol, ethanol, n-propanol, isopropanol,butanol, isobutanol, sec-butanol and, in particular, the C₅-C₁₂-alcoholsn-pentanol, n-hexanol, n-heptanol, n-octanol, n-nonanol, n-decanol,n-undecanol and n-dodecanol, and isomers thereof, glycols, for example1,2-ethylene glycol, 1,2- and 1,3-propylene glycol, 1,2-, 2,3- and1,4-butylene glycol, di- and triethylene glycol and di- and tripropyleneglycol, ethers, for example methyl tert-butyl ether, 1,2-ethylene glycolmono- and dimethyl ether, 1,2-ethylene glycol mono- and -diethylether,3-methoxypropanol, 3-isopropoxypropanol, tetrahydrofuran and dioxane,ketones, for example acetone, methyl ethyl ketone, methyl isobutylketone and diacetone alcohol (4-hydroxy-4-methyl-2-pentanone),C₁-C₅-alkyl esters, for example methyl acetate, ethyl acetate, propylacetate, butyl acetate and amyl acetate, aliphatic and aromatichydrocarbons, for example pentane, hexane, heptane, octane, isooctane,petroleum ether, toluene, xylene, ethylbenzene, tetralin, decalin,dimethylnaphthalene, white spirit, Shellsol® and Solvesso® mineral oils,for example gasoline, kerosine, diesel oil and heating oil, but alsonatural oils, for example olive oil, soya oil, rapeseed oil, linseed oiland sunflower oil.

It is of course also possible to use mixtures of these diluents in thecompositions according to the invention.

So long as there is at least partial miscibility, these diluents canalso be mixed with water. Examples of suitable diluents here areC1-C4-alcohols, for example methanol, ethanol, n-propanol, isopropanol,butanol, isobutanol and sec-butanol, glycols, for example 1,2-ethyleneglycol, 1,2- and 1,3-propylene glycol, 1,2-, 2,3- and 1,4-butyleneglycol, di- and triethylene glycol, and di- and tripropylene glycol,ethers, for example tetrahydrofuran and dioxane, ketones, for exampleacetone, methyl ethyl ketone and diacetone alcohol(4-hydroxy-4-methyl-2-pentanone), and C1-C4-alkyl esters, for examplemethyl, ethyl, propyl and butyl acetate.

The diluents are optionally employed in a proportion of from about 0 to10.0% by weight, preferably from about 0 to 5.0% by weight, based on thetotal weight of the polymerizable LC material.

The antifoams and deaerators (c1)), lubricants and flow auxiliaries(c2)), thermally curing or radiation-curing auxiliaries (c3)), substratewetting auxiliaries (c4)), wetting and dispersion auxiliaries (c5)),hydrophobicizing agents (c6)), adhesion promoters (c7)) and auxiliariesfor promoting scratch resistance (c8)) cannot strictly be delimited fromone another in their action.

For example, lubricants and flow auxiliaries often also act as antifoamsand/or deaerators and/or as auxiliaries for improving scratchresistance. Radiation-curing auxiliaries can also act as lubricants andflow auxiliaries and/or deaerators and/or as substrate wettingauxiliaries. In individual cases, some of these auxiliaries can alsofulfil the function of an adhesion promoter (c8)).

Corresponding to the above-said, a certain additive can therefore beclassified in a number of the groups c1) to c8) described below.

The antifoams in group c1) include silicon-free and silicon-containingpolymers. The silicon-containing polymers are, for example, unmodifiedor modified polydialkylsiloxanes or branched copolymers, comb or blockcopolymers comprising polydialkylsiloxane and polyether units, thelatter being obtainable from ethylene oxide or propylene oxide.

The deaerators in group c1) include, for example, organic polymers, forexample polyethers and polyacrylates, dialkylpolysiloxanes, inparticular dimethylpolysiloxanes, organically modified polysiloxanes,for example arylalkyl-modified polysiloxanes, and fluorosilicones.

The action of the antifoams is essentially based on preventing foamformation or destroying foam that has already formed. Antifoamsessentially work by promoting coalescence of finely divided gas or airbubbles to give larger bubbles in the medium to be deaerated, forexample the compositions according to the invention, and thus accelerateescape of the gas (of the air). Since antifoams can frequently also beemployed as deaerators and vice versa, these additives have beenincluded together under group c1).

Such auxiliaries are, for example, commercially available from Tego asTEGO® Foamex 800, TEGO® Foamex 805, TEGO® Foamex 810, TEGO® Foamex 815,TEGO® Foamex 825, TEGO® Foamex 835, TEGO® Foamex 840, TEGO® Foamex 842,TEGO® Foamex 1435, TEGO® Foamex 1488, TEGO® Foamex 1495, TEGO® Foamex3062, TEGO® Foamex 7447, TEGO® Foamex 8020, Tego® Foamex N, TEGO® FoamexK 3, TEGO® Antifoam 2-18, TEGO® Antifoam 2-18, TEGO® Antifoam 2-57,TEGO® Antifoam 2-80, TEGO® Antifoam 2-82, TEGO® Antifoam 2-89, TEGO®Antifoam 2-92, TEGO® Antifoam 14, TEGO® Antifoam 28, TEGO® Antifoam 81,TEGO® Antifoam D 90, TEGO® Antifoam 93, TEGO® Antifoam 200, TEGO®Antifoam 201, TEGO® Antifoam 202, TEGO® Antifoam 793, TEGO® Antifoam1488, TEGO® Antifoam 3062, TEGOPREN® 5803, TEGOPREN® 5852, TEGOPREN®5863, TEGOPREN® 7008, TEGO® Antifoam 1-60, TEGO® Antifoam 1-62, TEGO®Antifoam 1-85, TEGO® Antifoam 2-67, TEGO® Antifoam WM 20, TEGO® Antifoam50, TEGO® Antifoam 105, TEGO® Antifoam 730, TEGO® Antifoam MR 1015,TEGO® Antifoam MR 1016, TEGO® Antifoam 1435, TEGO® Antifoam N, TEGO®Antifoam KS 6, TEGO® Antifoam KS 10, TEGO® Antifoam KS 53, TEGO®Antifoam KS 95, TEGO® Antifoam KS 100, TEGO® Antifoam KE 600, TEGO®Antifoam KS 911, TEGO® Antifoam MR 1000, TEGO® Antifoam KS 1100, Tego®Airex 900, Tego® Airex 910, Tego® Airex 931, Tego® Airex 935, Tego®Airex 936, Tego® Airex 960, Tego® Airex 970, Tego® Airex 980 and Tego®Airex 985 and from BYK as BYK®-011, BYK®-019, BYK®-020, BYK®-021,BYK®-022, BYK®-023, BYK®-024, BYK®-025, BYK®-027, BYK®-031, BYK®-032,BYK®-033, BYK®-034, BYK®-035, BYK®-036, BYK®-037, BYK®-045, BYK®-051,BYK®-052, BYK®-053, BYK®-055, BYK®-057, BYK®-065, BYK®-066, BYK®-070,BYK®-080, BYK®-088, BYK®-141 and BYK®-A 530.

The auxiliaries in group c1) are optionally employed in a proportion offrom about 0 to 3.0% by weight, preferably from about 0 to 2.0% byweight, based on the total weight of the polymerizable LC material.

In group c2), the lubricants and flow auxiliaries typically includesilicon-free, but also silicon-containing polymers, for examplepolyacrylates or modifiers, low-molecular-weight polydialkylsiloxanes.The modification consists in some of the alkyl groups having beenreplaced by a wide variety of organic radicals. These organic radicalsare, for example, polyethers, polyesters or even long-chain(fluorinated)alkyl radicals, the former being used the most frequently.

The polyether radicals in the correspondingly modified polysiloxanes areusually built up from ethylene oxide and/or propylene oxide units.

Generally, the higher the proportion of these alkylene oxide units inthe modified polysiloxane, the more hydrophilic is the resultantproduct.

Such auxiliaries are, for example, commercially available from Tego asTEGO® Glide 100, TEGO® Glide ZG 400, TEGO® Glide 406, TEGO® Glide 410,TEGO® Glide 411, TEGO® Glide 415, TEGO® Glide 420, TEGO® Glide 435,TEGO® Glide 440, TEGO® Glide 450, TEGO® Glide A 115, TEGO® Glide B 1484(can also be used as antifoam and deaerator), TEGO® Flow ATF, TEGO® Flow300, TEGO® Flow 460, TEGO® Flow 425 and TEGO® Flow ZFS 460. Suitableradiation-curable lubricants and flow auxiliaries, which can also beused to improve the scratch resistance, are the products TEGO® Rad 2100,TEGO® Rad 2200, TEGO® Rad 2500, TEGO® Rad 2600 and TEGO® Rad 2700, whichare likewise obtainable from TEGO.

Such-auxiliaries are also available, for example, from BYK as BYK®-300BYK®-306, BYK®-307, BYK®-310, BYK®-320, BYK®-333, BYK®-341, Byk® 354,Byk®361, Byk®361N, BYK®388.

Such-auxiliaries are also available, for example, from 3M as FC4430®.

Such-auxiliaries are also available, for example, from Cytonix asFluorN®561 or FluorN®562.

Such-auxiliaries are also available, for example, from Merck KGaA asTivida® FL 2300 and Tivida® FL 2500

The auxiliaries in group c2) are optionally employed in a proportion offrom about 0 to 3.0% by weight, preferably from about 0 to 2.0% byweight, based on the total weight of the polymerizable LC material.

In group c3), the radiation-curing auxiliaries include, in particular,polysiloxanes having terminal double bonds which are, for example, aconstituent of an acrylate group. Such auxiliaries can be crosslinked byactinic or, for example, electron radiation. These auxiliaries generallycombine a number of properties together. In the uncrosslinked state,they can act as antifoams, deaerators, lubricants and flow auxiliariesand/or substrate wetting auxiliaries, while, in the crosslinked state,they increase, in particular, the scratch resistance, for example ofcoatings or films which can be produced using the compositions accordingto the invention. The improvement in the gloss properties, for exampleof precisely those coatings or films, is regarded essentially as aconsequence of the action of these auxiliaries as antifoams, deaeratorsand/or lubricants and flow auxiliaries (in the uncrosslinked state).

Examples of suitable radiation-curing auxiliaries are the products TEGO®Rad 2100, TEGO® Rad 2200, TEGO® Rad 2500, TEGO® Rad 2600 and TEGO® Rad2700 available from TEGO and the product BYK®-371 available from BYK.

Thermally curing auxiliaries in group c3) contain, for example, primaryOH groups, which are able to react with isocyanate groups, for exampleof the binder.

Examples of thermally curing auxiliaries, which can be used, are theproducts BYK®-370, BYK®-373 and BYK®-375 available from BYK.

The auxiliaries in group c3) are optionally employed in a proportion offrom about 0 to 5.0% by weight, preferably from about 0 to 3.0% byweight, based on the total weight of the polymerizable LC material.

The substrate wetting auxiliaries in group c4) serve, in particular, toincrease the wettability of the substrate to be printed or coated, forexample, by printing inks or coating compositions, for examplecompositions according to the invention. The generally attendantimprovement in the lubricant and flow behaviour of such printing inks orcoating compositions has an effect on the appearance of the finished(for example crosslinked) print or coating.

A wide variety of such auxiliaries are commercially available, forexample from Tego as TEGO® Wet KL 245, TEGO® Wet 250, TEGO® Wet 260 andTEGO® Wet ZFS 453 and from BYK as BYK®-306, BYK®-307, BYK®-310,BYK®-333, BYK®-344, BYK®-345, BYK®-346 and Byk®-348.

The auxiliaries in group c4) are optionally employed in a proportion offrom about 0 to 3.0% by weight, preferably from about 0 to 1.5% byweight, based on the total weight of the liquid-crystalline composition.

The wetting and dispersion auxiliaries in group c5) serve, inparticular, to prevent the flooding and floating and the sedimentationof pigments and are therefore, if necessary, suitable in particular inpigmented compositions.

These auxiliaries stabilize pigment dispersions essentially throughelectrostatic repulsion and/or steric hindrance of the pigment particlescontaining these additives, where, in the latter case, the interactionof the auxiliary with the ambient medium (for example binder) plays amajor role.

Since the use of such wetting and dispersion auxiliaries is commonpractice, for example in the technical area of printing inks and paints,the selection of a suitable auxiliary of this type generally does notpresent the person skilled in the art with any difficulties, if they areused.

Such wetting and dispersion auxiliaries are commercially available, forexample from Tego, as TEGO® Dispers 610, TEGO® Dispers 610 S, TEGO®Dispers 630, TEGO® Dispers 700, TEGO® Dispers 705, TEGO® Dispers 710,TEGO® Dispers 720 W, TEGO® Dispers 725 W, TEGO® Dispers 730 W, TEGO®Dispers 735 W and TEGO® Dispers 740 W and from BYK as Disperbyk®,Disperbyk®-107, Disperbyk®-108, Disperbyk®-110, Disperbyk®-111,Disperbyk®-115, Disperbyk®-130, Disperbyk®-160, Disperbyk®-161,Disperbyk®-162, Disperbyk®-163, Disperbyk®-164, Disperbyk®-165,Disperbyk®-166, Disperbyk®-167, Disperbyk®-170, Disperbyk®-174,Disperbyk®-180, Disperbyk®-181, Disperbyk®-182, Disperbyk®-183,Disperbyk®-184, Disperbyk®-185, Disperbyk®-190, Anti-Terra®-U,Anti-Terra®-U 80, Anti-Terra®-P, Anti-Terra®-203, Anti-Terra®-204,Anti-Terra®-206, BYK®-151, BYK®-154, BYK®-155, BYK®-P 104 S, BYK®-P 105,Lactimon®, Lactimon®-WS and Bykumen®.

The amount of the auxiliaries in group c5) used on the mean molecularweight of the auxiliary. In any case, a preliminary experiment istherefore advisable, but this can be accomplished simply by the personskilled in the art.

The hydrophobicizing agents in group c6) can be used to givewater-repellent properties to prints or coatings produced, for example,using compositions according to the invention. This prevents or at leastgreatly suppresses swelling due to water absorption and thus a changein, for example, the optical properties of such prints or coatings. Inaddition, when the composition is used, for example, as a printing inkin offset printing, water absorption can thereby be prevented or atleast greatly reduced.

Such hydrophobicizing agents are commercially available, for example,from Tego as Tego® Phobe WF, Tego® Phobe 1000, Tego® Phobe 1000 S, Tego®Phobe 1010, Tego® Phobe 1030, Tego® Phobe 1010, Tego® Phobe 1010, Tego®Phobe 1030, Tego® Phobe 1040, Tego® Phobe 1050, Tego® Phobe 1200, Tego®Phobe 1300, Tego® Phobe 1310 and Tego® Phobe 1400.

The auxiliaries in group c6) are optionally employed in a proportion offrom about 0 to 5.0% by weight, preferably from about 0 to 3.0% byweight, based on the total weight of the polymerizable LC material.

Further adhesion promoters from group c7) serve to improve the adhesionof two interfaces in contact. It is directly evident from this thatessentially the only fraction of the adhesion promoter that is effectiveis that located at one or the other or at both interfaces. If, forexample, it is desired to apply liquid or pasty printing inks, coatingcompositions or paints to a solid substrate, this generally means thatthe adhesion promoter must be added directly to the latter or thesubstrate must be pre-treated with the adhesion promoters (also known aspriming), i.e. this substrate is given modified chemical and/or physicalsurface properties.

If the substrate has previously been primed with a primer, this meansthat the interfaces in contact are that of the primer on the one handand of the printing ink or coating composition or paint on the otherhand. In this case, not only the adhesion properties between thesubstrate and the primer, but also between the substrate and theprinting ink or coating composition or paint play a part in adhesion ofthe overall multilayer structure on the substrate.

Adhesion promoters in the broader sense which may be mentioned are alsothe substrate wetting auxiliaries already listed under group c4), butthese generally do not have the same adhesion promotion capacity.

In view of the widely varying physical and chemical natures ofsubstrates and of printing inks, coating compositions and paintsintended, for example, for their printing or coating, the multiplicityof adhesion promoter systems is not surprising.

Adhesion promoters based on silanes are, for example,3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane,3-aminopropylmethyldiethoxysilane,N-aminoethyl-3-aminopropyltrimethoxysilane,N-aminoethyl-3-aminopropylmethyldimethoxysilane,N-methyl-3-aminopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane,3-methacryloyloxypropyltrimethoxysilane,3-glycidyloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane,3-chloropropyltrimethoxysilane and vinyltrimethoxysilane. These andother silanes are commercially available from Hüls, for example underthe tradename DYNASILAN®.

Corresponding technical information from the manufacturers of suchadditives should generally be used or the person skilled in the art canobtain this information in a simple manner through correspondingpreliminary experiments.

However, if these additives are to be added as auxiliaries from groupc7) to the polymerizable LC materials according to the invention, theirproportion optionally corresponds to from about 0 to 5.0% by weight,based on the total weight of the polymerizable LC material. Theseconcentration data serve merely as guidance, since the amount andidentity of the additive are determined in each individual case by thenature of the substrate and of the printing/coating composition.Corresponding technical information is usually available from themanufacturers of such additives for this case or can be determined in asimple manner by the person skilled in the art through correspondingpreliminary experiments.

The auxiliaries for improving the scratch resistance in group c8)include, for example, the abovementioned products TEGO® Rad 2100, TEGO®Rad 2200, TEGO® Rad 2500, TEGO® Rad 2600 and TEGO® Rad 2700, which areavailable from Tego.

For these auxiliaries, the amount data given for group c3) are likewisesuitable, i.e. these additives are optionally employed in a proportionof from about 0 to 5.0% by weight, preferably from about 0 to 3.0% byweight, based on the total weight of the liquid-crystalline composition.

Examples that may be mentioned of further light, heat and/or oxidationstabilizers are the following:

alkylated monophenols, such as 2,6-di-tert-butyl-4-methylphenol,2-tert-butyl-4,6-dimethylphenol, 2,6-di-tert-butyl-4-ethylphenol,2,6-di-tert-butyl-4-n-butylphenol, 2,6-di-tert-butyl-4-isobutylphenol,2,6-dicyclopentyl-4-methylphenol,2-(α-methylcyclohexyl)-4,6-dimethylphenol,2,6-dioctadecyl-4-methylphenol, 2,4,6-tricyclohexylphenol,2,6-di-tert-butyl-4-methoxymethylphenol, nonylphenols which have alinear or branched side chain, for example 2,6-dinonyl-4-methylphenol,2,4-dimethyl-6-(1′-methylundec-1′-yl)phenol,2,4-dimethyl-6-(1′-methylheptadec-1′-yl)phenol,2,4-dimethyl-6-(1′-methyltridec-1′-yl)phenol and mixtures of thesecompounds, alkylthiomethylphenols, such as2,4-dioctylthiomethyl-6-tert-butylphenol,2,4-dioctylthiomethyl-6-methylphenol,2,4-dioctylthiomethyl-6-ethylphenol and2,6-didodecylthiomethyl-4-nonylphenol,Hydroquinones and alkylated hydroquinones, such as2,6-di-tert-butyl-4-methoxyphenol, 2,5-di-tert-butylhydroquinone,2,5-di-tert-amylhydrocrainone, 2,6-diphenyl-4-octadecyloxyphenol,2,6-di-tert-butylhydroquinone, 2,5-di-tert-butyl-4-hydroxyanisole,3,5-di-tert-butyl-4-hydroxyanisole, 3,5-di-tert-butyl-4-hydroxyphenylstearate and bis(3,5-di-tert-butyl-4-hydroxyphenyl)adipate,Tocopherols, such as α-tocopherol, β-tocopherol, γ-tocopherol,5-tocopherol and mixtures of these compounds, and tocopherolderivatives, such as tocopheryl acetate, succinate, nicotinate andpolyoxyethylenesuccinate (“tocofersolate”),hydroxylated diphenyl thioethers, such as2,2′-thiobis(6-tert-butyl-4-methylphenol), 2,2′-thiobis(4-octylphenol),4,4′-thiobis(6-tert-butyl-3-methylphenol),4,4′-thiobis(6-tert-butyl-2-methylphenol),4,4′-thiobis(3,6-di-sec-amylphenol) and4,4′-bis(2,6-dimethyl-4-hydroxyphenyl)disulfide,Alkylidenebisphenols, such as2,2′-methylenebis(6-tert-butyl-4-methylphenol),2,2′-methylenebis(6-tert-butyl-4-ethylphenol),2,2′-methylenebis[4-methyl-6-(α-methylcyclohexyl)phenol],2,2′-methylenebis(4-methyl-6-cyclohexylphenol),2,2′-methylenebis(6-nonyl-4-methylphenol),2,2′-methylenebis(4,6-di-tert-butylphenol),2,2-ethylidenebis(4,6-di-tert-butylphenol),2,2′-ethylidenebis(6-tert-butyl-4-isobutylphenol),2,2′-methylenebis[6-(α-methylbenzyl)-4-nonylphenol],2,2′-methylenebis[6-(α,α-dimethylbenzyl)-4-nonylphenol],4,4′-methylenebis(2,6-di-tert-butylphenol),4,4′-methylenebis(6-tert-butyl-2-methylphenol),1,1-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)butane,2,6-bis(3-tert-butyl-5-methyl-2-hydroxybenzyl)-4-methylphenol,1,1,3-tris(5-tert-butyl-4-hydroxy-2-methylphenyl)butane,1,1-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)-3-n-dodecyl-mercaptobutane,ethylene glycol bis[3,3-bis(3′-tert-butyl-4′-hydroxyphenyl)butyrate],bis(3-tert-butyl-4-hydroxy-5-methylphenyl)dicyclopentadiene,bis[2-(3′-tert-butyl-2′-hydroxy-5′-methylbenzyl)-6-tert-butyl-4-methylphenyl]terephthalate,1,1-bis(3,5-dimethyl-2-hydroxyphenyl)butane,2,2-bis(3,5-di-tert-butyl-4-hydroxyphenyl)propane,2,2-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)-4-n-dodecyl-mercaptobutaneand 1,1,5,5-tetrakis(5-tert-butyl-4-hydroxy-2-methylphenyl)pentane,O—, N- and S-benzyl compounds, such as3,5,3′,5′-tetra-tert-butyl-4,4′-dihydroxydibenzyl ether, octadecyl4-hydroxy-3,5-dimethylbenzylmercaptoacetate, tridecyl4-hydroxy-3,5-di-tert-butylbenzylmercaptoacetate,tris(3,5-di-tert-butyl-4-hydroxybenzyl)amine,bis(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)dithioterephthalate,bis(3,5-di-tert-butyl-4-hydroxybenzyl)sulfide andisooctyl-3,5-di-tert-butyl-4-hydroxybenzylmercaptoacetate,aromatic hydroxybenzyl compounds, such as1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-trimethyl-benzene,1,4-bis(3,5-di-tert-butyl-4-hydroxybenzyl)-2,3,5,6-tetramethyl-benzeneand 2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)phenol,Triazine compounds, such as2,4-bis(octylmercapto)-6-(3,5-di-tert-butyl-4-hydroxyanilino)-1,3,5-triazine,2-octylmercapto-4,6-bis(3,5-di-tert-butyl-4-hydroxyanilino)-1,3,5-triazine,2-octylmercapto-4,6-bis(3,5-di-tert-butyl-4-hydroxyphenoxy)-1,3,5-triazine,2,4,6-tris(3,5-di-tert-butyl-4-hydroxyphenoxy)-1,2,3-triazine,1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate,1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate,2,4,6-tris(3,5-di-tert-butyl-4-hydroxyphenylethyl)-1,3,5-triazine,1,3,5-tris-(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hexahydro-1,3,5-triazine,1,3,5-tris(3,5-dicyclohexyl-4-hydroxybenzyl)isocyanurate and1,3,5-tris(2-hydroxyethyl)isocyanurate,Benzylphosphonates, such as dimethyl2,5-di-tert-butyl-4-hydroxybenzylphosphonate, diethyl3,5-di-tert-butyl-4-hydroxybenzylphosphonate, dioctadecyl3,5-di-tert-butyl-4-hydroxybenzylphosphonate and dioctadecyl5-tert-butyl-4-hydroxy-3-methylbenzylphosphonate,Acylaminophenols, such as 4-hydroxylauroylanilide,4-hydroxystearoylanilide and octylN-(3,5-di-tert-butyl-4-hydroxyphenyl)carbamate,Propionic and acetic esters, for example of monohydric or polyhydricalcohols, such as methanol, ethanol, n-octanol, i-octanol, octadecanol,1,6-hexanediol, 1,9-nonanediol, ethylene glycol, 1,2-propanediol,neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethyleneglycol, pentaerythritol, tris(hydroxyethyl)isocyanurate,N,N′-bis(hydroxyethyl)oxalamide, 3-thiaundecanol, 3-thiapentadecanol,trimethylhexanediol, trimethylolpropane and4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]-octane,Propionamides based on amine derivatives, such asN,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hexamethylenediamine,N,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)trimethylenediamineand N,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazine,Ascorbic acid (Vitamin C) and ascorbic acid derivatives, such asascorbyl palmitate, laurate and stearate, and ascorbyl sulfate andphosphate,Antioxidants based on amine compounds, such asN,N′-diisopropyl-p-phenylenediamine,N,N′-di-sec-butyl-p-phenylenediamine,N,N′-bis(1,4-dimethylpentyl)-p-phenylenediamine,N,N′-bis(1-ethyl-3-methylpentyl)-p-phenylenediamine,N,N′-bis(1-methylheptyl)-p-phenylenediamine,N,N′-dicyclohexyl-p-phenylenediamine, N,N′-diphenyl-p-phenylenediamine,N,N′-bis(2-naphthyl)-p-phenylenediamine,N-isopropyl-N′-phenyl-p-phenylenediamine,N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine,N-(1-methylheptyl)-N′-phenyl-p-phenylenediamine,N-cyclohexyl-N′-phenyl-p-phenylenediamine,4-(p-toluenesulfamoyl)diphenylamine,N,N′-dimethyl-N,N′-di-sec-butyl-p-phenylenediamine, diphenylamine,N-allyldiphenylamine, 4-isopropoxydiphenylamine,N-phenyl-1-naphthylamine, N-(4-tert-octylphenyl)-1-naphthylamine,N-phenyl-2-naphthylamine, octyl-substituted diphenylamine, such asp,p′-di-tert-octyldiphenylamine, 4-n-butylaminophenol,4-butyrylaminophenol, 4-nonanoylaminophenol, 4-dodecanoylaminophenol,4-octadecanoylaminophenol, bis[4-methoxyphenyl)amine,2,6-di-tert-butyl-4-dimethylaminomethylphenol,2,4-diaminodiphenylmethane, 4,4′-diaminodiphenylmethane,N,N,N′,N′-tetramethyl-4,4′-diaminodiphenylmethane,1,2-bis[(2-methylphenyl)amino]ethane, 1,2-bis(phenylamino)propane,(o-tolyl)biguanide, bis[4-(1′,3′-dimethylbutyl)phenyl]amine,tert-octyl-substituted N-phenyl-1-naphthylamine, a mixture of mono- anddialkylated tert-butyl/tert-octyldiphenylamine, a mixture of mono- anddialkylated nonyldiphenylamine, a mixture of mono- and dialkylateddodecyldiphenylamine, a mixture of mono- and dialkylatedisopropyl/isohexyldiphenylamine, a mixture of mono- and dialkylatedtert-butyldiphenylamine, 2,3-dihydro-3,3-dimethyl-4H-1,4-benzothiazine,phenothiazine, a mixture of mono- and dialkylatedtert-butyl/tert-octylphenothiazine, a mixture of mono- and dialkylatedtert-octylphenothiazine, N-allylphenothiazine,N,N,N′,N′-tetraphenyl-1,4-diaminobut-2-ene,N,N-bis(2,2,6,6-tetramethylpiperidin-4-yl)hexamethylenediamine,bis(2,2,6,6-tetramethylpiperidin-4-yl)sebacate,2,2,6,6-tetramethylpiperidin-4-one and2,2,6,6-tetramethylpiperidin-4-ol,Phosphines, phosphites and phosphonites, such as triphenylphosninetriphenylphosphite, diphenyl alkyl phosphite, phenyl dialkyl phosphite,tris(nonylphenyl)phosphite, trilauryl phosphite, trioctadecyl phosphite,distearyl pentaerythritol diphosphite,tris(2,4-di-tert-butylphenyl)phosphite, diisodecyl pentaerythritoldiphosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite,bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite,diisodecyloxy pentaerythritol diphosphite,bis(2,4-di-tert-butyl-6-methylphenyl)pentaerythritol diphosphite,bis(2,4,6-tris(tert-butylphenyl))pentaerythritol diphosphite, tristearylsorbitol triphosphite,tetrakis(2,4-di-tert-butylphenyl)4,4′-biphenylenediphosphonite,6-isooctyloxy-2,4,8,10-tetra-tert-butyl-12H-dibenz[d,g]-1,3,2-dioxaphosphocine,6-fluoro-2,4,8,10-tetra-tert-butyl-12-methyl-dibenz[d,g]-1,3,2-dioxaphosphocine,bis(2,4-di-tert-butyl-6-methylphenyl)methyl phosphite andbis(2,4-di-tert-butyl-6-methylphenyl)ethyl phosphite,2-(2′-Hydroxyphenyl)benzotriazoles, such as2-(2′-hydroxy-5′-methylphenyl)benzotriazole,2-(3′,5′-di-tert-butyl-2′-hydroxyphenyl)benzotriazole,2-(5′-tert-butyl-2′-hydroxyphenyl)benzotriazole,2-(2′-hydroxy-5′-(1,1,3,3-tetramethylbutyl)phenyl)benzotriazole,2-(3′,5′-di-tert-butyl-2′-hydroxyphenyl)-5-chlorobenzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-methylphenyl)-5-chlorobenzotriazole,2-(3′-sec-butyl-5′-tert-butyl-2′-hydroxyphenyl)benzotriazole,2-(2′-hydroxy-4′-octyloxyphenyl)benzotriazole,2-(3′,5′-di-tert-amyl-2′-hydroxyphenyl)benzotriazole,2-(3,5′-bis-(α,α-dimethylbenzyl)-2′-hydroxyphenyl)benzotriazole, amixture of2-(3′-tert-butyl-2′-hydroxy-5′-(2-octyloxycarbonylethyl)phenyl)-5-chlorobenzotriazole,2-(3′-tert-butyl-5′-[2-(2-ethylhexyloxy)carbonylethyl]-2′-hydroxyphenyl)-5-chlorobenzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-(2-methoxycarbonylethyl)phenyl)-5-chlorobenzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-(2-methoxycarbonylethyl)phenyl)benzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-(2-octyloxycarbonylethyl)phenyl)benzotriazole,2-(3′-tert-butyl-5′-[2-(2-ethylhexyloxy)carbonylethyl]-2′-hydroxyphenyl)benzotriazole,2-(3′-dodecyl-2′-hydroxy-5′-methylphenyl)benzotriazole and2-(3′-tert-butyl-2′-hydroxy-5′-(2-isooctyloxycarbonylethyl)phenylbenzotriazole,2,2′-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-benzotriazol-2-ylphenol];the product of complete esterification of2-[3′-tert-butyl-5′-(2-methoxycarbonylethyl)-2′-hydroxyphenyl]-2H-benzotriazolewith polyethylene glycol 300;sulfur-containing peroxide scavengers and sulfur-containingantioxidants, such as esters of 3,3′-thiodipropionic acid, for examplethe lauryl, stearyl, myristyl and tridecyl esters, mercaptobenzimidazoleand the zinc salt of 2-mercaptobenzimidazole, dibutylzincdithiocarbamates, dioctadecyl disulfide and pentaerythritoltetrakis(β-dodecylmercapto)propionate,2-hydroxybenzophenones, such as the 4-hydroxy, 4-methoxy, 4-octyloxy,4-decycloxy, 4-dodecyloxy, 4-benzyloxy, 4,2′,4′-trihydroxy and2′-hydroxy-4,4′-dimethoxy derivatives,Esters of unsubstituted and substituted benzoic acids, such as4-tert-butylphenyl salicylate, phenyl salicylate, octylphenylsalicylate, dibenzoylresorcinol, bis(4-tert-butylbenzoyl)resorcinol,benzoylresorcinol, 2,4-di-tert-butylphenyl3,5-di-tert-butyl-4-hydroxybenzoate,hexadecyl-3,5-di-tert-butyl-4-hydroxybenzoate,octadecyl-3,5-di-tert-butyl-4-hydroxybenzoate and2-methyl-4,6-di-tert-butylphenyl-3,5-di-tert-butyl-4-hydroxybenzoate,Acrylates, such as ethyl α-cyano-β,β-diphenylacrylate, isooctylα-cyano-β,β-diphenylacrylate, methyl α-methoxycarbonylcinnamate, methylα-cyano-p-methyl-p-methoxycinnamate,butyl-α-cyano-p-methyl-p-methoxycinnamate andmethyl-α-methoxycarbonyl-p-methoxycinnamate, sterically hindered amines,such as bis(2,2,6,6-tetramethylpiperidin-4-yl)sebacate,bis(2,2,6,6-tetramethylpiperidin-4-yl)succinate,bis(1,2,2,6,6-pentamethylpiperidin-4-yl)sebacate,bis(1-octyloxy-2,2,6,6-tetramethylpiperidin-4-yl)sebacate,bis(1,2,2,6,6-pentamethylpiperidin-4-yl)-n-butyl-3,5-di-tert-butyl-4-hydroxybenzylmalonate,the condensation product of1-(2-hydroxyethyl)-2,2,6,6-tetramethyl-4-hydroxypiperidine and succinicacid, the condensation product ofN,N′-bis(2,2,6,6-tetramethylpiperidin-4-yl)hexamethylenediamine and4-tert-octylamino-2,6-dichloro-1,3,5-triazine,tris(2,2,6,6-tetramethylpiperidin-4-yl)nitrilotriacetate,tetrakis(2,2,6,6-tetramethylpiperidin-4-yl)1,2,3,4-butanetetracarboxylate,1,1′-(1,2-ethylene)bis(3,3,5,5-tetramethylpiperazinone),4-benzoyl-2,2,6,6-tetramethylpiperidine,4-stearyloxy-2,2,6,6-tetramethylpiperidine,bis(1,2,2,6,6-pentamethylpiperidin-4-yl)2-n-butyl-2-(2-hydroxy-3,5-di-tert-butylbenzyl)malonate,3-n-octyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decane-2,4-dione,bis(1-octyloxy-2,2,6,6-tetramethylpiperidin-4-yl)sebacate,bis(1-octyloxy-2,2,6,6-tetramethylpiperidin-4-yl)succinate, thecondensation product ofN,N′-bis(2,2,6,6-tetramethylpiperidin-4-yl)hexamethylenediamine and4-morpholino-2,6-dichloro-1,3,5-triazine, the condensation product of2-chloro-4,6-bis(4-n-butylamino-2,2,6,6-tetramethylpiperidin-4-yl)-1,3,5-triazineand 1,2-bis(3-aminopropylamino)ethane, the condensation product of2-chloro-4,6-di(4-n-butylamino-1,2,2,6,6-pentamethylpiperidin-4-yl)-1,3,5-triazineand 1,2-bis(3-aminopropylamino)ethane,8-acetyl-3-dodecyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]-decane-2,4-dione,3-dodecyl-1-(2,2,6,6-tetramethylpiperidin-4-yl)pyrrolidine-2,5-dione,3-dodecyl-1-(1,2,2,6,6-pentamethylpiperidin-4-yl)pyrrolidine-2,5-dione,a mixture of 4-hexadecyloxy- and4-stearyloxy-2,2,6,6-tetramethylpiperidine, the condensation product ofN,N′-bis(2,2,6,6-tetramethylpiperidin-4-yl)hexamethylenediamine and4-cyclohexylamino-2,6-dichloro-1,3,5-triazine, the condensation productof 1,2-bis(3-aminopropylamino)ethane and 2,4,6-trichloro-1,3,5-triazine,4-butylamino-2,2,6,6-tetramethylpiperidine,N-(2,2,6,6-tetramethylpiperidin-4-yl)-n-dodecylsuccinimide,N-(1,2,2,6,6-pentamethylpiperidin-4-yl)-n-dodecylsuccinimide,2-undecyl-7,7,9,9-tetramethyl-1-oxa-3,8-diaza-4-oxo-spiro[4.5]-decane,the condensation product of7,7,9,9-tetramethyl-2-cycloundecyl-1-oxa-3,8-diaza-4-oxospiro-[4.5]decaneand epichlorohydrin, the condensation products of4-amino-2,2,6,6-tetramethylpiperidine with tetramethylolacetylenediureasandpoly(methoxypropyl-3-oxy)-[4(2,2,6,6-tetramethyl)piperidinyl]-siloxane,Oxalamides, such as 4,4′-dioctyloxyoxanilide, 2,2′-diethoxyoxanilide,2,2′-dioctyloxy-5,5′-di-tert-butoxanilide,2,2′-didodecyloxy-5,5′-di-tert-butoxanilide, 2-ethoxy-2′-ethyloxanilide,N,N′-bis(3-dimethylaminopropyl)oxalamide,2-ethoxy-5-tert-butyl-2′-ethoxanilide and its mixture with2-ethoxy-2′-ethyl-5,4′-di-tert-butoxanilide, and mixtures of ortho-,para-methoxy-disubstituted oxanilides and mixtures of ortho- andpara-ethoxy-disubstituted oxanilides, and2-(2-hydroxyphenyl)-1,3,5-triazines, such as2,4,6-tris-(2-hydroxy-4-octyloxyphenyl)-1,3,5-triazine,2-(2-hydroxy-4-octyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-(2,4-dihydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2,4-bis(2-hydroxy-4-propyloxyphenyl)-6-(2,4-dimethylphenyl)-1,3,5-triazine,2-(2-hydroxy-4-octyloxyphenyl)-4,6-bis(4-methylphenyl)-1,3,5-triazine,2-(2-hydroxy-4-dodecyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-(2-hydroxy-4-tridecyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-[2-hydroxy-4-(2-hydroxy-3-butyloxypropoxy)phenyl]-4,6-bis(2,4-dimethyl)-1,3,5-triazine,2-[2-hydroxy-4-(2-hydroxy-3-octyloxypropoxy)phenyl]-4,6-bis(2,4-dimethyl)-1,3,5-triazine,2-[4-(dodecyloxy/tridecyloxy-2-hydroxypropoxy)-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-[2-hydroxy-4-(2-hydroxy-3-dodecyloxypropoxy)phenyl]-4,6-bis-(2,4-dimethylphenyl)-1,3,5-triazine,2-(2-hydroxy-4-hexyloxyphenyl)-4,6-diphenyl-1,3,5-triazine,2-(2-hydroxy-4-methoxyphenyl)-4,6-diphenyl-1,3,5-triazine,2,4,6-tris[2-hydroxy-4-(3-butoxy-2-hydroxypropoxy)phenyl]-1,3,5-triazineand 2-(2-hydroxyphenyl)-4-(4-methoxyphenyl)-6-phenyl-1,3,5-triazine.

In another preferred embodiment, the polymerizable LC material comprisesone or more specific antioxidant additives, preferably selected from theIrganox® series, e.g. the commercially available antioxidantsIrganox®1076 and Irganox®1010, from Ciba, Switzerland.

In another preferred embodiment, the polymerizable LC material comprisesa combination of one or more, more preferably of two or morephotoinitiators, for example, selected from the commercially availableIrgacure® or Darocure® (Ciba AG) series, in particular, Irgacure 127,Irgacure 184, Irgacure 369, Irgacure 651, Irgacure 817, Irgacure 907,Irgacure 1300, Irgacure, Irgacure 2022, Irgacure 2100, Irgacure 2959, orDarcure TPO, further selected from the commercially available OXE02(Ciba AG), NCI 930, N1919T (Adeka), SPI-03 or SPI-04 (Samyang).

The concentration of the polymerization initiator(s) as a whole in thepolymerizable LC material is preferably from 0.5 to 10%, very preferablyfrom 0.8 to 8%, more preferably 1 to 6%.

In a preferred embodiment, the polymerizable LC material is dissolved ina suitable solvent, which are preferably selected from organic solvents.

The solvents are preferably selected from ketones such as acetone,methyl ethyl ketone, methyl propyl ketone, methyl isobutyl ketone orcyclohexanone; acetates such as methyl, ethyl or butyl acetate or methylacetoacetate; alcohols such as methanol, ethanol or isopropyl alcohol;aromatic solvents such as toluene or xylene; alicyclic hydrocarbons suchas cyclopentane or cyclohexane; halogenated hydrocarbons such as di- ortrichloromethane; glycols or their esters such as PGMEA (propyl glycolmonomethyl ether acetate), γ-butyrolactone. It is also possible to usebinary, ternary or higher mixtures of the above solvents. In particular,for multilayer applications, methyl iso butyl ketone is the preferredutilized solvent

In case the polymerizable LC material contains one or more solvents, thetotal concentration of all solids, including the RMs, in the solvent(s)is preferably from 10 to 60%, more preferably from 20 to 50%, inparticular from 30 to 45%

Preferably, the polymerizable LC material comprises besides one or moreblock copolymers,

-   -   a) one or more polymerizable mesogenic compounds of formula RMT        and corresponding subformulae,    -   b) optionally one or more multi- or direactive polymerizable        mesogenic compounds, preferably selected from compounds of        formula DRM and corresponding subformulae,    -   c) one or more chiral mesogenic compounds, preferably selected        from compounds of formula CRMa to CRMc, more preferably of CRMb,        and its subformulae,    -   d) optionally one or more monoreactive mesogens, preferably        selected from compounds of formula MRM and corresponding        subformulae,    -   e) optionally one or more photoinitiators,    -   f) optionally one or more antioxidative additives,    -   g) optionally one or more adhesion promotors,    -   h) optionally one or more surfactants,    -   i) optionally one or more mono-, di- or multireactive        polymerizable non-mesogenic compounds,    -   j) optionally one or more dyes showing an absorption maximum at        the wavelength used to initiate photo polymerization,    -   k) optionally one or more chain transfer agents,    -   l) optionally one or more further stabilizers,    -   m) optionally one or more lubricants and flow auxiliaries, and    -   n) optionally one or more diluents,    -   o) optionally a non-polymerizable nematic component,    -   p) optionally one or more organic solvents.

More preferably, the polymerizable LC material comprises,

-   -   a) one or more block copolymers as given above, or its        corresponding preferred subformulae,    -   b) one or more, preferably two or more polymerizable mesogenic        compounds of formula RMT and corresponding subformulae,        preferably selected from compounds of subformulae RMTa2-A4,        and/or RMTa2-A5 and/or RMTb-A3    -   c) one or more, preferably two or more, direactive polymerizable        mesogenic compounds, preferably selected from the compounds of        formula DRMa-1,    -   d) optionally one or more, preferably two or more, monoreactive        polymerizable mesogenic compounds, preferably selected from        compounds of formulae MRM-1, and/or MRM-4, and/or MRM-6, and/or        MRM-7,    -   e) optionally one or more chiral mesogenic compounds of formula        CRMb, in particular of formula CRMb-1 bl,    -   f) optionally one or more antioxidative additives, preferably        selected from esters of unsubstituted and substituted benzoic        acids, in particular Irganox®1076, and if present, preferably in        an amount of 0.01 to 2% by weight, very preferably 0.05 to 1% by        weight,    -   g) optionally one or more photoinitiators, preferably        Irgacure®907, and/or SPI-3    -   h) optionally one or more organic solvents, preferably methyl        isobutyl ketone.

The invention further relates to a method of preparing a polymer film by

-   -   providing a layer of a polymerizable LC material as described        above and below onto a substrate,    -   polymerizing the polymerizable components of the polymerizable        LC material by photopolymerization, and    -   optionally removing the polymerized LC material from the        substrate and/or optionally providing it onto another substrate.

This polymerizable LC material can be coated or printed onto thesubstrate, for example by spin-coating, printing, or other knowntechniques, and the solvent is evaporated off before polymerization. Inmost cases, it is suitable to heat the mixture in order to facilitatethe evaporation of the solvent.

The polymerizable LC material can be applied onto a substrate byconventional coating techniques like spin coating, bar coating or bladecoating. It can also be applied to the substrate by conventionalprinting techniques which are known to the expert, like for examplescreen printing, offset printing, reel-to-reel printing, letter pressprinting, gravure printing, rotogravure printing, flexographic printing,intaglio printing, pad printing, heat-seal printing, ink-jet printing orprinting by means of a stamp or printing plate.

Suitable substrate materials and substrates are known to the expert anddescribed in the literature, as for example conventional substrates usedin the optical films industry, such as glass or plastic. Especiallysuitable and preferred substrates for polymerization are polyester suchas polyethyleneterephthalate (PET) or polyethylenenaphthalate (PEN),polyvinylalcohol (PVA), polycarbonate (PC) triacetylcellulose (TAC), orcyclo olefin polymers (COP), or commonly known color filter materials,in particular triacetylcellulose (TAC), cyclo olefin polymers (COP), orcommonly known colour filter materials.

The polymerizable LC material preferably exhibits a uniform alignmentthroughout the whole layer. Preferably, the polymerizable LC materialexhibits a uniform planar, a uniform homeotropic, uniform cholesteric orpatterned alignment.

The Friedel-Creagh-Kmetz rule can be used to predict whether a mixturewill adopt planar or homeotropic alignment, by comparing the surfaceenergies of the RM layer (γ_(RM)) and the substrate (γ_(s)):

If γ_(RM)>γ_(s) the reactive mesogenic compounds will displayhomeotropic alignment, If γ_(RM)<γ_(s) the reactive mesogenic compoundswill display homogeneous alignment.

Without to be bound by theory, when the surface energy of a substrate isrelatively low, the intermolecular forces between the reactive mesogensare stronger than the forces across the RM-substrate interface andconsequently, reactive mesogens align perpendicular to the substrate(homeotropic alignment) in order to maximise the intermolecular forces.

Homeotropic alignment can also be achieved by using amphiphilicmaterials; they can be added directly to the polymerizable LC material,or the substrate can be treated with these materials in the form of ahomeotropic alignment layer. The polar head of the amphiphilic materialchemically bonds to the substrate, and the hydrocarbon tail pointsperpendicular to the substrate. Intermolecular interactions between theamphiphilic material and the RMs promote homeotropic alignment. Commonlyused amphiphilic surfactants are described above.

Another method used to promote homeotropic alignment is to apply coronadischarge treatment to plastic substrates, generating alcohol or ketonefunctional groups on the substrate surface. These polar groups caninteract with the polar groups present in RMs or surfactants to promotehomeotropic alignment.

When the surface tension of the substrate is greater than the surfacetension of the RMs, the force across the interface dominates. Theinterface energy is minimised if the reactive mesogens align parallelwith the substrate, so the long axis of the RM can interact with thesubstrate. One way planar alignment can be promoted is by coating thesubstrate with a polyimide layer, and then rubbing the alignment layerwith a velvet cloth.

Other suitable planar alignment layers are known in the art, like forexample rubbed polyimide or alignment layers prepared by photoalignmentas described in U.S. Pat. Nos. 5,602,661, 5,389,698 or 6,717,644.

In general, reviews of alignment techniques are given for example by I.Sage in “Thermotropic Liquid Crystals”, edited by G. W. Gray, John Wiley& Sons, 1987, pages 75-77; and by T. Uchida and H. Seki in “LiquidCrystals—Applications and Uses Vol. 3”, edited by B. Bahadur, WorldScientific Publishing, Singapore 1992, pages 1-63. A further review ofalignment materials and techniques is given by J. Cognard, Mol. Cryst.Liq. Cryst. 78, Supplement 1 (1981), pages 1-77.

For the production of the polymer films according to the invention, thepolymerizable compounds in the polymerizable LC material are polymerizedor crosslinked (if one compound contains two or more polymerizablegroups) by in-situ photopolymerization.

The photopolymerization can be carried out in one step. It is alsopossible to photopolymerize or crosslink the compounds in a second step,which have not reacted in the first step (“end curing”).

In a preferred method of preparation the polymerizable LC material iscoated onto a substrate and subsequently photopolymerized for example byexposure to actinic radiation as described for example in WO 01/20394,GB 2,315,072 or WO 98/04651.

Photopolymerization of the LC material is preferably achieved byexposing it to actinic radiation. Actinic radiation means irradiationwith light, like UV light, IR light or visible light, irradiation withX-rays or gamma rays, or irradiation with high-energy particles, such asions or electrons. Preferably, polymerization is carried out by photoirradiation, in particular with UV light. As a source for actinicradiation, for example a single UV lamp or a set of UV lamps can beused. When using a high lamp power the curing time can be reduced.Another possible source for photo radiation is a laser, like e.g. a UVlaser, an IR laser, or a visible laser. Another possible source forphoto radiation is a LED lamp.

The curing time is dependent, inter alia, on the reactivity of thepolymerizable LC material, the thickness of the coated layer, the typeof polymerization initiator and the power of the UV lamp. The curingtime is preferably 5 minutes, very preferably 3 minutes, most preferably<1 minute. For mass production, short curing times of <30 seconds arepreferred.

A suitable UV radiation power is preferably in the range from 5 to 200mWcm-2, more preferably in the range from 50 to 175 mWcm⁻² and mostpreferably in the range from 100 to 150 mWcm-2.

In connection with the applied UV radiation and as a function of time, asuitable UV dose is preferably in the range from 25 to 7200 mJcm⁻² morepreferably in the range from 100 to 7200 mJcm⁻² and most preferably inthe range from 200 to 7200 mJcm⁻².

Photopolymerization is preferably performed under an inert gasatmosphere, preferably in a heated nitrogen atmosphere, but alsopolymerization in air is possible.

Photopolymerization is preferably performed at a temperature from 1 to70° C., more preferably 5 to 50° C., even more preferably 15 to 30° C.

The polymerized LC film according to the present invention has goodadhesion to plastic substrates, in particular to TAC, COP, and colourfilters. Accordingly, it can be used as adhesive or base coating forsubsequent LC layers which otherwise would not well adhere to thesubstrates.

For optical applications of the polymer film, it preferably has athickness of from 0.5 to 10 μm, very preferably from 0.5 to 5 μm, inparticular from 0.5 to 3 μm.

The optical retardation (δ(λ)) of a polymer film as a function of thewavelength of the incident beam (λ) is given by the following equation(7):

δ(k)=(2πΔn·d)/λ  (7)

wherein (Δn) is the birefringence of the film, (d) is the thickness ofthe film and λ is the wavelength of the incident beam.

According to Snellius law, the birefringence as a function of thedirection of the incident beam is defined as

Δn=sin Θ/sin Ψ  (8)

wherein sin Θ is the incidence angle or the tilt angle of the opticalaxis in the film and sin Ψ is the corresponding reflection angle.

Based on these laws, the birefringence and accordingly opticalretardation depends on the thickness of a film and the tilt angle ofoptical axis in the film (cf. Berek's compensator). Therefore, theskilled expert is aware that different optical retardations or differentbirefringence can be induced by adjusting the orientation of theliquid-crystalline molecules in the polymer film.

The birefringence (Δn) of the polymer film according to the presentinvention is preferably in the range from 0.01 to 0.4, more preferablein the range from 0.01 to 0.3 and even more preferable in the range from0.01 to 0.25.

The optical retardation as a function of the thickness of the polymerfilm according to the present invention is less than 200 nm, preferableless than 180 nm and even more preferable less than 150 nm.

The polymer film of the present invention can also be used as alignmentfilm or substrate for other liquid-crystalline or RM materials. Theinventors have found that the polymer film obtainable from apolymerizable LC material as described above and below, is in particularuseful for multilayer applications due to its improved dewettingcharacteristics. In this way, stacks of optical films or preferablypolymerized LC films can be prepared.

In summary, the polymerized LC films and polymerizable LC materialsaccording to the present invention are useful in optical elements likepolarisers, compensators, alignment layer, circular polarisers or colourfilters in liquid crystal displays or projection systems, decorativeimages, for the preparation of liquid crystal or effect pigments, andespecially in reflective films with spatially varying reflectioncolours, e.g. as multicolour image for decorative, information storageor security uses, such as non-forgeable documents like identity orcredit cards, banknotes etc.

The polymerized LC films according to the present invention can be usedin displays of the transmissive or reflective type. They can be used inconventional OLED displays or LCDs, in particular LCDs.

The present invention is described above and below with particularreference to the preferred embodiments. It should be understood thatvarious changes and modifications might be made therein withoutdeparting from the spirit and scope of the invention.

Many of the compounds or mixtures thereof mentioned above and below arecommercially available. All of these compounds are either known or canbe prepared by methods which are known per se, as described in theliterature (for example in the standard works such as Houben-Weyl,Methoden der Organischen Chemie [Methods of Organic Chemistry],Georg-Thieme-Verlag, Stuttgart), to be precise under reaction conditionswhich are known and suitable for said reactions. Use may also be madehere of variants which are known per se, but are not mentioned here.

It will be appreciated that variations to the foregoing embodiments ofthe invention can be made while still falling within the scope of theinvention. Alternative features serving the same, equivalent, or similarpurpose may replace each feature disclosed in this specification, unlessstated otherwise. Thus, unless stated otherwise, each feature disclosedis one example only of a generic series of equivalent or similarfeatures.

All of the features disclosed in this specification may be combined inany combination, except combinations where at least some of suchfeatures and/or steps are mutually exclusive. In particular, thepreferred features of the invention are applicable to all aspects of theinvention and may be used in any combination. Likewise, featuresdescribed in non-essential combinations may be used separately (not incombination).

It will be appreciated that many of the features described above,particularly of the preferred embodiments, are inventive in their ownright and not just as part of an embodiment of the present invention.Independent protection may be sought for these features in addition toor alternative to any invention presently claimed.

The invention will now be described in more detail by reference to thefollowing working examples, which are illustrative only and do not limitthe scope of the invention.

EXAMPLES Example 1

The following formulations are prepared in accordance with the giventables:

Formulation 1 Surfactant 0.500% Irganox 1076 0.080% LC756 4.100% LC2425.000% SPI-03 2.500%

2.000%

2.000%

2.500%

3.000%

5.080%

8.000%

15.000% 

50.240%  Formulation 2 Surfactant 0.250% Irganox 1076 0.080% LC7564.100% LC242 5.000% SPI-03 2.500%

2.000%

2.000%

2.500%

3.000%

5.080%

8.000%

15.000% 

50.490%  Formulation 3 Surfactant 0.125% Irganox 1076 0.080% LC7564.100% LC242 5.000% SPI-03 2.500%

2.000%

2.000%

2.500%

3.000%

5.080%

8.000%

15.000% 

50.615%  Formulation 4 Surfactant 0.062% Irganox 1076 0.080% LC7564.100% LC242 5.000% SPI-03 2.500%

2.000%

2.000%

2.500%

3.000%

5.080%

8.000%

15.000% 

50.678% 

Irganox 1076, LC756 and LC242 are commercially available from BASF,Germany; SPI-3 is commercially available from Samyang Corporation,Korea.

The formulations 1 to 4 are dissolved to 20% solids in MIBK (methylisobutyl ketone): 3-Pentanone (8:2). Each host formulation was thendoped with various surfactants to create final formulations shown in thefollowing table.

Surfactant Doped Formulations in Each Host

Formulation Surfactant 1 2 3 4 Tego Airex Formulation FormulationFormulation Formulation 901  5 17 29 41 Tego Airex FormulationFormulation Formulation Formulation 920  6 18 30 42 Tego AirexFormulation Formulation Formulation Formulation 931  7 19 31 43 TegoAirex Formulation Formulation Formulation Formulation 962  8 20 32 44Tego Glide Formulation Formulation Formulation Formulation 435  9 21 3345 Tego Wet Formulation Formulation Formulation Formulation 260 10 22 3446 Tego Wet Formulation Formulation Formulation Formulation 500 11 23 3547 Tego Wet Formulation Formulation Formulation Formulation 510 12 24 3648 Polyfox Formulation Formulation Formulation Formulation PF-3320 13 2537 49 Polyfox Formulation Formulation Formulation Formulation PF-7002 1426 38 50 Polyfox Formulation Formulation Formulation Formulation PF-65615 27 39 51 Tego Twin Formulation Formulation Formulation Formulation4000 16 28 40 52

Tego Airex 901, Tego Airex 920, Tego Airex 931, Tego Airex 962, TegoGlide 435, Tego Wet 260, Tego Wet 500, Tego Wet 510, Tego Twin 4000 arecommercially available from Evonik Tego, Germany. Polyfox PF-3320Polyfox PF-7002 Polyfox PF-656 are commercially available from OmnovaSolutions Inc., USA.

The formulations 5-52 are spin coated on polyimide rubbed glass at 1000rpm for 30 s, respectively. The wet films are annealed at 60° C. for 60s and cured in Light Hammer 6 Fusion conveyor belt UV lamp (250 mJ cm⁻²)under N2. Each resulting film is visually inspected for CLC alignmentand visible haze by eye after initial cure. An additional coat of thesame formulation was coated on top following the same method as givenabove. Each multiple layer coating is visually inspected for dewettingafter the second annealing step.

Comparative Formulations:

Formulation Surfactant Alignment in Dewets in Alignment in No. conc. 1stCoating 2nd Coating 2nd Coating Formulation 5 0.500% ○ X X Formulation17 0.250% ○ X X Formulation 29 0.125% ○ X X Formulation 41 0.062% ○ X XFormulation 6 0.500% ○ X X Formulation 18 0.250% ○ X X Formulation 300.125% ○ X X Formulation 42 0.062% ○ X X Formulation 7 0.500% X ○ XFormulation 19 0.250% X X X Formulation 31 0.125% X X X Formulation 430.062% ○ X X Formulation 8 0.500%

X ○ Formulation 20 0.250% ○ X ○ Formulation 32 0.125% ○ ○ ○ Formulation44 0.062% ○ ○

Formulation 9 0.500% ○ X X Formulation 21 0.250% ○ X X Formulation 330.125% ○ X X Formulation 45 0.062% ○ X X Formulation 10 0.500% ○ ○ XFormulation 22 0.250%

○ ○ Formulation 34 0.125% ○ ○ ○ Formulation 46 0.062% ○ ○

Formulation 11 0.500%

○ X Formulation 23 0.250% X X X Formulation 35 0.125% X X X Formulation47 0.062% X X X Formulation 12 0.500%

○ X Formulation 24 0.250% X X X Formulation 36 0.125% X X X Formulation48 0.062% X X X Formulation 13 0.500% ○ X X Formulation 25 0.250% ○ X XFormulation 37 0.125% ○ X X Formulation 49 0.062% ○ X X Formulation 160.500% ○ X X Formulation 28 0.250% ○ X X Formulation 40 0.125% ○ X

Formulation 52 0.062% ○

○

Formulations According to the Invention:

Formulation Surfactant Alignment in Dewets in Alignment in No. conc. 1stCoating 2nd Coating 2nd Coating Formulation 15 0.500% ○ ○ X Formulation27 0.250% ○ ○ ○ Formulation 39 0.125% ○ ○ ○ Formulation 51 0.062% ○ ○ ○Formulation 14 0.500%

○ Formulation 26 0.250% ○ X ○ Formulation 38 0.125% ○ ○ ○ Formulation 500.062% ○

-   -   O=Good (Good alignment or no dewets)    -   Δ=Bad (acceptable CLC alignment/haze or some dewets)    -   X=(Extreme dewets)

As can be seen in the above-given table, using Polyfox PF-656(formulations 15, 27, 39, and 51) as the surfactant offers an extremelywide range of concentrations that can be used to achieve CLC alignment.This surfactant choice also has a wide range of concentrations where itdoes not cause dewetting of subsequent coated layers and also providesalignment to upper layers so an extra alignment layer is not requiredbetween CLC layers. Similar results could be obtained with PolyFox PF7002 (formulations 14, 26, 38, and 50).

Example 2

The following formulations are prepared in accordance with the giventables:

Formulation 53 Polyfox 656 0.03% Irganox 1076 0.080%  SPI-03 2.500% 

4.050% 

4.500% 

13.000% 

75.840%  Formualtion 54 Polyfox 656 0.03% Irganox 1076 0.08% SPI-032.50%

3.71%

4.50%

13.00% 

76.18%  Formulation 55 Polyfox 656 0.03% Irganox 1076 0.08% SPI-03 2.50%

3.38%

4.50%

13.00% 

76.51%  Formulation 56 Polyfox 656 0.03% Irganox 1076 0.08% SPI-03 2.50%

3.04%

4.50%

13.00% 

76.85%  Formulation 57 Polyfox 656 0.03% Irganox 1076 0.08% SPI-03 2.50%

2.70%

4.50%

13.00% 

77.19% 

Each formulation is dissolved to 20% solids in MIBK: 3-Pentanone (8:2)The formulations 53-57 are bar coated on 5× rubbed cyclic olefin polymersubstrate using Mayer Bar 9 respectively. The wet films are annealed at6000 for 60 s and cured in Light Hammer 6 Fusion conveyor belt UV lamp(250 mJ cm⁻²) under N2. Each film is visually inspected for CLCalignment by eye after cure. No film crystallization or dewetting wasobserved for any of the coated films. Each film is measured using aShimadzu 3600 UV-Vis spectrometer to determine the reflective wavelengthand bandwidth of reflection. Film thicknesses were measured using aDektak Profilometer. The results of these measurements are shown in thetable below.

Central Wavelength Reflection Bandwidth Film Thickness in nm in nm in μmFilm 1 467 72 5.14 Film 2 504 76 5.75 Film 3 550 85 4.77 Film 4 610 965.38 Film 5 681 115  5.13

Example 3

The following formulations are prepared in accordance with the giventables:

Formulation 58 Polyfox 656 0.03% Irganox 1076 0.08% SPI-03 2.50%

4.05%

4.500% 

13.00% 

75.84%  Formulation 59 Polyfox 656 0.03% Irganox 1076 0.08% SPI-03 2.50%

3.04%

4.50%

13.00% 

76.85% 

The formulations are dissolved to 40% solids in MIBK: 3-Pentanone (8:2)The formulations 58 and 59 are spin coated on polyimide rubbed glass at1000 rpm for 30 s, respectively. The wet films are annealed at 60° C.for 60 s and cured in Light Hammer 6 Fusion conveyor belt UV lamp (250mJ cm⁻²) under N₂.

Each film is visually inspected for CLC alignment and visible haze byeye after initial cure Film 6 obtained from formulation 58 showsexcellent alignment and exhibits a main Reflection Bandwidth from 425 to510 Film 7 obtained from Formulation 59 shows excellent alignment andexhibits a main Reflection Bandwidth from 550 to 675 nm.

Film 8 is obtained from a multilayer coating of formulation 59 which iscoated and cured as given above, followed by formulation 58 coated andcured as given above on top of the polymer film obtained fromformulation 59. The multilayer film exhibits one Reflection Bandwidthfrom 425 to 510 nm and a second main Reflection Bandwidth from 550 to675 nm

It can be seen that using Polyfox PF656 surfactant, it is possible tocoat one CLC film on top of another directly with wide bandwidths foreach of the layers. There is also no detrimental effect on reflectionproperties of each layer as can be seen with the overlapping reflectionbands.

1. A polymerizable LC material, comprising one or more reactivemesogenic compounds, one or more chiral compounds, and a block copolymerthat comprises at least one polyfluorooxetane block bonded to apolyether block, wherein said polyfluorooxetane block has one or morerepeating units of the formula

wherein each n and m are each and independently an integer from 1 to 6,R is hydrogen or an alkyl group having from 1 to 6 carbon atoms, R_(f)and R_(f*) are each and independently a linear or branched alkyl groupof from 1 to about 20 carbon atoms with a minimum of 50% of the hydrogenatoms of said R_(f) or R_(f*) alkyl group being replaced by F, andoptionally up to all of the remaining H atoms being replaced by I, Cl,or Br, DP is from 2 to about
 100. 2. The polymerizable LC materialaccording to claim 1, having a concentration of the block copolymer offrom 0.01% to 1%.
 3. The polymerizable LC material according to claim 1,comprising one or more reactive mesogens of formula RMT,

wherein P is a polymerizable group, Sp is a spacer group or a singlebond, r2 and r3 are independently of each other 0, 1, 2, 3 or 4, R¹¹ isβ-Sp-, alkyl, alkoxy, thioalkyl, alkylcarbonyl, alkoxycarbonyl,alkylcarbonyloxy or alkoxycarbonyloxy that is optionally fluorinated. Aand B denote, in case of multiple occurrence independently of oneanother, an aromatic or alicyclic group, which optionally contains oneor more heteroatoms selected from N, O and S, and is optionally mono- orpolysubstituted by L, wherein one or two non-adjacent CH₂ groups areoptionally replaced by O and/or S, wherein these groups areunsubstituted or substituted by 1, 2, 3 or 4 groups L L is β-Sp-, F, Cl,Br, I, —CN, —NO₂, —NCO, —NCS, —OCN, —SCN, —C(═O)NR^(x)R^(y),—C(═O)OR^(x), —C(═O)R^(x), —NR^(x)R^(y), —OH, —SF₅, or straight chain orbranched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxyor alkoxycarbonyloxy with 1 to 12 C atoms, wherein one or more H atomsare optionally replaced by F, Cl, —CN, or straight chain or branchedalkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy oralkoxycarbonyloxy with 1 to 6 C atoms, R^(x) and R^(y) independently ofeach other denote H or alkyl with 1 to 12 C-atoms, Z¹¹ and Z¹² denotes,in case of multiple occurrence independently of one another, —O—, —S—,—CO—, —COO—, —OCO—, —S—CO—, —CO—S—, —O—COO—, —CO—NR⁰⁰—, —NR⁰⁰—CO—,—NR⁰⁰—CO—NR⁰⁰, —NR⁰⁰—CO—O—, —O—CO—NR⁰⁰—, —OCH₂—, —CH₂O—, —SCH₂—, —CH₂S—,—CF₂O—, —OCF₂—, —CF₂S—, —SCF₂—, —CH₂CH₂—, —(CH₂)_(n1), —CF₂CH₂—,—CH₂CF₂—, —CF₂CF₂—, —CH═N—, —N═CH—, —N═N—, —CH═CR⁰⁰—, —CY¹═CY²—, —C≡C—,—CH═CH—COO—, —OCO—CH═CH— or a single bond, Y¹ and Y² independently ofeach other denote H, F, Cl or CN, n is 1, 2, 3 or 4, m is 0, 1, 2, 3 or4, and n1 is an integer from 1 to 10, preferably 1, 2, 3 or
 4. 4. Thepolymerizable LC material according to claim 3, having a concentrationof compounds of formula RMT of from 40% to 99%.
 5. The polymerizable LCmaterial according to claim 1, comprising one or more compounds offormula DRM,P¹-Sp¹-MG-Sp²-P²  DRM wherein P¹ and P² independently of each otherdenote a polymerizable group, Sp¹ and Sp² independently of each otherare a spacer group or a single bond, and MG is a rod-shaped mesogenicgroup, wherein compounds of formula RMT are excluded from the compoundsof formula DRM.
 6. The polymerizable LC material according to claim 1,having a concentration of di- or multireactive reactive mesogens of from1% to 60%.
 7. The polymerizable LC material according to claim 1,comprising one or more compounds of formula MRM:P¹-Sp¹-MG-R  MRM wherein P¹ and P² independently of each other denote apolymerizable group, Sp¹ and Sp² independently of each other are aspacer group or a single bond, and MG is a rod-shaped mesogenic group, Rdenotes β-Sp-, F, Cl, Br, I, —CN, —NO₂, —NCO, —NCS, —OCN, —SCN,—C(═O)NR^(x)R^(y), —C(═O)X, —C(═O)OR^(x), —C(═O)R^(y), —NR^(x)R^(y),—OH, —SF₅, optionally substituted silyl, straight chain or branchedalkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy oralkoxycarbonyloxy with 1 to 12 C atoms, wherein one or more H atoms areoptionally replaced by F or Cl, X is halogen, and R^(x) and R^(y) areindependently of each other H or alkyl with 1 to 12 C atoms, whereincompounds of formula RMT are excluded from the compound of formula MRM.8. The polymerizable LC material according to claim 1, comprising one ormore reactive chiral compounds selected from compounds of formula CRMato CRMc,

wherein P^(0*) denotes a polymerizable group P Sp* denotes a spacer SpA⁰ and B⁰ are, in case of multiple occurrence independently of oneanother, 1,4-phenylene that is unsubstituted or substituted with 1, 2, 3or 4 groups L as defined above, or trans-1,4-cyclohexylene, X¹ and X²are independently of each other —O—, —COO—, —OCO—, —O—CO—O— or a singlebond, Z^(0*) is, in case of multiple occurrence independently of oneanother, —COO—, —OCO—, —O—CO—O—, —OCH₂—, —CH₂O—, —CF₂O—, —OCF₂—,—CH₂CH₂—, —(CH₂)₄—, —CF₂CH₂—, —CH₂CF₂—, —CF₂CF₂—, —C≡C—, —CH═CH—,—CH═CH—COO—, —OCO—CH═CH— or a single bond, t is, independently of eachother 0, 1, 2 or 3, a is 0, 1 or 2, b is 0 or an integer from 1 to 12, zis 0 or 1, and wherein the naphthalene rings in formula CRMa canadditionally be substituted with one or more identical or differentgroups L wherein L is, independently of each other F, Cl, CN,halogenated alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl,alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 5 C atoms.
 9. Thepolymerizable LC material according to claim 1, having a concentrationof chiral compounds in the liquid-crystalline medium of from 1 to 20%.10. The polymerizable LC material according to claim 1, comprising oneor more additives selected from the group consisting of surfactants,photo initiators, stabilisers, catalysts, sensitizers, inhibitors,chain-transfer agents, co-reacting monomers, reactive thinners,surface-active compounds, lubricating agents, wetting agents, dispersingagents, hydrophobing agents, adhesive agents, flow improvers, degassingor defoaming agents, deaerators, diluents, reactive diluents,auxiliaries, colourants, dyes, pigments and nanoparticles.
 11. A processfor the preparation of a polymerizable LC material, comprising the stepsof mixing one or more block copolymers comprising at least onepolyfluorooxetane block bonded to a polyether block, wherein saidpolyfluorooxetane block has one or more repeating units of the formula

wherein each n and m are each and independently an integer from 1 to 6,R is hydrogen or an alkyl group having from 1 to 6 carbon atoms, R_(f)and R_(f*) are each and independently a linear or branched alkyl groupof from 1 to about 20 carbon atoms with a minimum of 50% of the hydrogenatoms of said R_(f) or R_(f*) alkyl group being replaced by F, andoptionally up to all of the remaining H atoms being replaced by I, Cl,or Br, and DP is from 2 to about 100, with one or more reactivemesogenic compounds and one or more chiral compounds.
 12. A process forthe preparation of the of a polymer film, comprising the steps of:providing a layer of a polymerizable LC material according to claim 1onto a substrate, photopolymerizing the polymerizable LC material, andoptionally removing the polymerized LC material from the substrateand/or optionally providing it onto another substrate.
 13. A polymerfilm obtainable from a polymerizable LC material by a process comprisingthe steps of: providing a layer of a polymerizable LC material accordingto claim 1 onto a substrate, photopolymerizing the LC material, andoptionally, removing the polymerized LC material from the substrateand/or optionally providing it onto another substrate.
 14. An opticalcomponent comprising the polymer film according to claim
 13. 15. Anoptical component comprising the polymerizable LC material according toclaim
 1. 16. An electro optical device comprising the optical componentaccording to claim
 14. 17. An electro optical device comprising thepolymer film according to claim
 13. 18. An electro optical devicecomprising the polymerizable LC material according to claim
 1. 19. Thepolymerizable LC material according to claim 3, wherein R¹¹ is β-Sp-,alkyl, alkoxy, thioalkyl, alkylcarbonyl, alkoxycarbonyl,alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 15 C atoms, A and Bdenote, in case of multiple occurrence independently of one another,1,4-phenylene, pyridine-2,5-diyl, pyrimidine-2,5-diyl,thiophene-2,5-diyl, naphthalene-2,6-diyl,1,2,3,4-tetrahydro-naphthalene-2,6-diyl, indane-2,5-diyl,bicyclooctylene, or 1,4-cyclohexylene, Z¹¹ and Z¹² denotes, in case ofmultiple occurrence independently of one another, —COO—, —OCO—, —C≡C—,or a single bond, n is 1 or 2, and m is 0 or
 1. 20. The polymerizable LCmaterial according to claim 5, wherein MG is a rod-shaped mesogenicgroup of formula MG-(A¹-Z¹)_(n)-A²-  MG wherein A¹ and A² denote, in case of multipleoccurrence independently of one another, an aromatic or alicyclic group,which optionally contains one or more heteroatoms selected from N, O andS, and is optionally mono- or polysubstituted by L, L is β-Sp-, F, Cl,Br, I, —CN, —NO₂, —NCO, —NCS, —OCN, —SCN, —C(═O)NR^(x)R^(y),—C(═O)OR^(x), —C(═O)R^(x), —NR^(x)R^(y), —OH, —SF₅, optionallysubstituted silyl, aryl or heteroaryl with 1 to 12, preferably 1 to 6 Catoms, and straight chain or branched alkyl, alkoxy, alkylcarbonyl,alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 12 Catoms, wherein one or more H atoms are optionally replaced by F or Cl,R^(x) and R^(y) independently of each other denote H or alkyl with 1 to12 C atoms, Z¹ denotes, in case of multiple occurrence independently ofone another, —O—, —S—, —CO—, —COO—, —OCO—, —S—CO—, —CO—S—, —O—COO—,—CO—NR^(x)—, —NR^(x)—CO—, —NR^(x)—CO—NR^(y), —NR^(x)—CO—O—,—O—CO—NR^(x)—, —OCH₂—, —CH₂O—, —SCH₂—, —CH₂S—, —CF₂O—, —OCF₂—, —CF₂S—,—SCF₂—, —(CH₂)_(n1), —CF₂CH₂—, —CH₂CF₂—, —CF₂CF₂—, —CH═N—, —N═CH—,—N═N—, —CH═CR^(x)—, —CY¹═CY²—, —C≡C—, —CH═CH—COO—, —OCO—CH═CH— or asingle bond, Y¹ and Y² independently of each other denote H, F, Cl orCN, n is 1, 2, 3 or 4, and n1 is an integer from 1 to
 10. 21. Thepolymerizable LC material of claim 7, wherein MG is a rod-shapedmesogenic group of formula MG-(A¹-Z¹)_(n)-A²-  MG wherein A¹ and A² denote, in case of multipleoccurrence independently of one another, an aromatic or alicyclic group,which optionally contains one or more heteroatoms selected from N, O andS, and is optionally mono- or polysubstituted by L, L is β-Sp-, F, Cl,Br, I, —CN, —NO₂, —NCO, —NCS, —OCN, —SCN, —C(═O)NR^(x)R^(y),—C(═O)OR^(x), —C(═O)R^(x), —NR^(x)R^(y), —OH, —SF₅, optionallysubstituted silyl, aryl or heteroaryl with 1 to 12, preferably 1 to 6 Catoms, and straight chain or branched alkyl, alkoxy, alkylcarbonyl,alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 12 Catoms, wherein one or more H atoms are optionally replaced by F or Cl,R^(x) and R^(y) independently of each other denote H or alkyl with 1 to12 C atoms, Z¹ denotes, in case of multiple occurrence independently ofone another, —O—, —S—, —CO—, —COO—, —OCO—, —S—CO—, —CO—S—, —O—COO—,—CO—NR^(x)—, —NR^(x)—CO—, —NR^(x)—CO—NR^(y), —NR^(x)—CO—O—,—O—CO—NR^(x)—, —OCH₂—, —CH₂O—, —SCH₂—, —CH₂S—, —CF₂O—, —OCF₂—, —CF₂S—,—SCF₂—, —(CH₂)_(n1), —CF₂CH₂—, —CH₂CF₂—, —CF₂CF₂—, —CH═N—, —N═CH—,—N═N—, —CH═CR^(x)—, —CY¹═CY²—, —C≡C—, —CH═CH—COO—, —OCO—CH═CH— or asingle bond, Y¹ and Y² independently of each other denote H, F, Cl orCN, n is 1, 2, 3 or 4, and n1 is an integer from 1 to 10.